THE  UNIVERSITY 
OF  ILLINOIS 
LIBRARY 

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Digitized  by  the  Internet  Archive 
in  2016 


https://archive.org/details/montanastatebure16mont 


UNIVERSITY  OF  MONTANA  BULLETIN 

BUREAU  OF  MINES  AND  METALLURGY  SERIES  NO.  1 


The  Montana  State  Bureau 

OF 

Mines  and  Metallurgy 


frit  UiihWr  OF  THE 

FE3  2 6 1925 

UNIVERSITY  OF  ILLINOIS 


STATE  SCHOOL  OF  MINES 
BUTTE,  MONTANA 
MAY,  1919 


Entered  at  Butte,  Montana,  as  second-class  matter  under  Act  of  Congress, 
August  24,  1912 


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M 763 ll. 


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STATE  BUREAU  OF  MINES  AND  METALLURGY 

STAFF 


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CLAPP,  CHARLES  H.  -----  - Director  and  Geology 

PhD.,  Massachusetts  Institute  of  Technology,  1910 

ADAMI,  ARTHUR  E.  - --  --  --  Mining  Engineer 

E.  M.,  Montana  State  School  of  Mines,  1907 

PULSIFER,  H.  B.  ------  - Metallurgy  and  Safety 

B.  S.,  Massachusetts  Institute  of  Technology,  1903; 

Ch.E.,  Armour  Institute  of  Technology,  1915; 

M.  S.,  University  of  Chicago,  1918. 


873305 


FOREWORD 

The  purpose  of  this  Bulletin  is  to  call  attention  to  the  fact  that  the 
Legislative  Assembly  of  the  State  of  Montana,  for  the  year  1919,  estab- 
lished in  the  State  School  of  Mines  of  the  University  of  Montana  a 
State  Bureau  of  Mines  and  Metallurgy.  The  Bureau  was  established 
to  aid  in  the  development  of  the  mineral  resources  of  Montana.  In 
much  the  same  way  that  the  Agricultural  Experiment  Station  at 
Bozeman  has  furthered  the  agricultural  industry  of  the  State,  the 
Bureau  of  Mines  and  Metallurgy  will  stand  ready  to  assist  and  pro- 
mote the  mineral  industry.  The  Bureau  has  been  established  primariU 
for  service,  and,  as  far  as  is  reasonable,  those  interested  may  avail 
themselves  of  its  services  free  of  charge. 


— 4 — 


CREATION  OF  BUREAU  AND  APPROPRIATION 


The  bill  creating  the  Montana  State  Bureau  of  Mines  and  Metal- 
lurgy, enacted  by  the  Legislative  Assembly  of  Montana  for  1919 
(Chapter  161,  page  311),  was  introduced  by  Representative  Arthur  V. 
Corry,  a Mining  Engineer  of  Butte.  The  Bureau  was  established  as  a 
department  of  the  State  School  of  Mines  of  the  University  of  Montana, 
and  is  under  the  direction  of  the  State  Board  of  Education,  which 
appoints  the  director.  The  regular  and  special  reports  of  the  Bureau 
are  to  be  printed  and  distributed  as  the  State  Board  of  Education  may 
direct,  and  as  the  interests  of  the  State  and  of  science  and  industry 
may  demand.  All  materials  collected,  after  having  served  the  purposes 
of  the  Bureau,  are  to  be  deposited  either  in  State  museums  or  in  the 
collections  of  the  State  School  of  Mines,  and  duplicates  of  represen- 
tative material  are  to  be  distributed  to  the  various  educational  insti- 
tutions of  the  State,  so  as  to  be  of  the  greatest  educational  advantage. 

A fund  of  $20,000.00,  necessary  for  the  maintenance  of  the  Bureau, 
was  appropriated  for  the  biennium  ending  February  28,  1921. 


OBJECT  AND  DUTIES 

The  Bureau  was  established  primarily  for  the  purpose  of  promoting 
the  development  of  the  mineral  resources  of  the  State,  and  of  increas- 
ing the  safety  and  efficiency  of  mining  and  its  allied  operations.  A 
bureau  is  the  best  medium  for  collecting  information  concerning  the 
mineral  resources  and  industry,  and  of  disseminating  such  information 
by  answering  inquiries  and  by  the  publication  of  bulletins.  It  is  also 
an  efficient  agent  in  the  practical  solution  of  the  problems  of  con- 
servation. 

Conservation  is  now  taken  by  most  practical  men  to  mean:  “Utili- 
zation, with  a maximum  efficiency  and  a minimum  waste.”  This  defi- 
nition applies  particularly  to  conservation  in  the  mining  industry,  for, 
unlike  agricultural  products,  which  are  annually  replenished,  the 
product  of  the  mines  consists  of  only  one  crop,  which  must  meet  the 
future,  as  well  as  the  present  needs. 

To  conserve  their  mineral  reserves,  large  organizations  are  forced 
by  the  stress  of  circumstances  to  mine,  mill,  and  smelt  their  ores 
efficiently,  and  to  conserve  the  services  and  lives  of  their  employees 
they  are  forced  to  mine,  mill,  and  smelt  their  ores  safely.  Individuals 
and  companies  operating  small  mines  and  prospects,  of  which  there 
are  several  hundred  within  the  State,  do  not  fail  to  appreciate  the 
need  for  efficient  and  safe  operation,  but  can  rarely  give  to  these 
matters  the  attention  and  money  necessary  to  achieve  the  best  results. 
To  assist  these  men  by.  helping  them  mine  more  profitably,  under 


— 5 — 


safer  and  more  healthful  conditions,  will  be  a great  factor  in  conser- 
vation. 

The  object  and  duties  of  the  Bureau,  as  specified  by  law,  are  as 
follows: 

1.  To  collect,  to  compile,  and  to  publish  statistics,  relative  to 
Montana  geology,  mining,  milling,  and  metallurgy. 

2.  To  collect  typical  geological  and  mineral  specimens  and  samples 
of  products;  to  collect  photographs,  models,  and  drawings  of  appli- 
ances used  in  the  mines,  mills,  and  smelters  of  Montana. 

3.  To  collect  a library  and  a bibliography  of  literature  pertaining 
to  or  useful  for  the  progress  of  geology,  mining,  milling,  and  smelting- 
in  Montana. 

4.  To  study  the  geological  formations  of  the  State  with  special 
reference  to  their  economic  mineral  resources,  both  metallic  and  non- 
metallic. 

5.  To  examine  the  topography  and  physical  features  of  the  State 
with  reference  to  their  practical  bearing  upon  the  occupation  of  the 
people. 

6.  To  study  the  mining,  milling,  and  smelting  operations  carried 
on  in  the  State,  with  special  reference  to  their  improvement. 

7.  To  prepare  and  to  publish  bulletins  and  reports,  with  necessary 
illustrations  and  maps,  which  shall  embrace  both  a general  and  a 
detailed  description  of  the  natural  resources  and  geology,  mines,  mills, 
and  reduction  plants  of  the  State. 

8.  To  make  qualitative  examinations  of  rocks  and  mineral  samples. 

9.  To  consider  such  other  scientific  and  economic  problems  as  in 
the  judgment  of  the  State  Board  of  Education  are  of  value  to  the 
people  of  the  State. 

10.  • To  communicate  special  information  on  Montana  geology, 
mining,  and  metallurgy. 

11.  To  co-operate  with  the  other  departments  of  the  University 
of  Montana,  with  the  State  Mine  Inspector,  and  with  other  depart- 
ments of  the  State  Government  as  may  be  mutually  beneficial;  and 
to  co-operate  with  the  United  States  Geological  Survey  and  with 
the  United  States  Bureau  of  Mines,  in  accordance  with  the  regulations 
of  those  institutions. 

It  might  be  wondered  by  some,  why  the  Bureau  should  not  under- 
take to  make  assays  and  chemical  quantitative  analyses  free  of  charge. 
These  matters,  however,  naturally  fall  to  the  private  assayer  and 
chemist,  for  the  State  should  not  enter  into  competition  with  the 
legitimate  private  business  of  its  citizens.  However,  qualitative  tests 
of  samples  can  be  made  and  many  questions  concerning  the  com- 
mercial value  of  the  samples  may  be  answered.  Samples,  ores,  and 
other  consignments  should  be  shipped  to  the  State  Bureau  of  Mines 
and  Metallurgy,  Butte,  Montana,  preferably  by  parcel  post,  except  in 
the  case  of  large  consignments. 


— 6 — 


ORGANIZATION 


The  Bureau  is  organized  into  four  major  departments — Adminis- 
trative, Geology,  Mining,  and  Metallurgy  and  Safety.  The  Adminis- 
trative Department  directs  the  work  of  the  Bureau,  sees  that  requests 
for  information  are  referred  to  the  proper  departments  for  answer, 
supervises  the  co-operative  work,  oversees  the  printing,  publication, 
and  distribution  of  the  reports  of  the  Bureau,  and  prepares  for  the 
State  Board  of  Education  the  biennial  report  to  the  Legislative 
Assembly. 

The  Geological  Department  undertakes  the  study  of  the  geological 
formations  and  mineral  resources  of  the  State, -collects  geological  and 
mineral  specimens,  makes  qualitative  examinations  of  rocks  and 
mineral  samples,  and  prepares  geological  reports. 

The  Mining  Department  makes  the  necessary  surveys  and  prepares 
topographic  and  other  base  maps,  studies  the  mining  operations  of  the 
State,  and  prepares  reports  on  mining  operations. 

The  Metallurgical  and  Safety  Department  collects  statistics  with 
regard  to  the  mineral  industry  of  the  State,  studies  the  milling  and 
smelting  operations,  engages  in  metallurgical  research,  and  prepares 
reports  on  metallurgy  and  safety. 

PLAN  OF  WORK 

Work  for  which  there  is  special  and  immediate  demand  will  receive 
first  attention,  and  that  which  is  planned  for  the  biennium  1919-1921 
consists  of  the  preparation  of  a report  on  the  Mining  Districts  of 
Montana,  giving  location  of  districts,  accessibility,  valuable  products, 
statistics  of  production,  summary  of  geological  features,  and  a bibli- 
ography of  available  maps  and  literature;  and  the  preparation  of 
reports  on  the  various  mineral  products  of  current  interest,  such  as 
oil  and  gas,  gypsum,  and  road-building  material. 

The  Mining  Department  is  undertaking  the  preparation  of  a report 
on  mining  methods  and  timbering  for  prospects  and  small  mines. 

Besides  collecting  statistics  on  the  mineral  resources  of  the  State, 
the  Metallurgical  and  Safety  Department  will  study  conditions  of 
safety,  welfare,  and  hygiene  in  the  appropriate  industries  and  will 
prepare  circulars  on  the  advance  of  this  phase  of  industry  in  other 
communities.  It  will  also  undertake  to  standardize  small  shipments  of 
mineral  products  and  ores;  engage  in  research  in  the  structure  of 
copper  and  other  metals,  with  a view  of  determining  the  relation  of 
the  structure  of  metals  to  the  physical  properties;  and  will  prepare 
bulletins  on  the  theory  and  application  of  flotation  and  the  ball  mill 
to  small  mining  properties,  and  on  the  cyanide  process  as  used  in 
Montana. 

Application  has  been  made  to  the  United  States  Geological  Survey 
and  United  States  Bureau  of  Mines  to  engage  in  co-operative  work 
with  the  State  Bureau.  Much  good  should  result  from  the  proposed 
co-operation,  for  similar  co-operation  has  been  proved,  in  certain  parts 


— 7 — . 


of  the  United  States,  to  be  very  successful  and  beneficial.  Attention 
will  also  be  drawn  to*  the  desirability  of  securing  a United  States 
Bureau  of  Mines  Experiment  Station  in  Butte. 

PUBLICATIONS 

The  results  of  the  work  of  the  bureau  will  be  made  accessible  to 
the  public  by  the  publication  of  bulletins  and  circulars.  These  will  be 
sent  free  of  charge  to  those  requesting  them.  The  publication  of 
pertinent  material  through  local  co-operation  with  mining  companies, 
chambers  of  commerce,  and  newspapers  should  be  of  direct  and  imme- 
diate benefit  to  the  people  of  the  State. 

The  demand  for  individual  correspondence,  such  as  heretofore  has 
been  carried  on  by  the  School  of  Mines,  and  which  grew  to  such 
volume  as  to  interfere  with  the  regular  work  of  the  school,  was  one 
important  factor  leading  to  the  establishment  of  the  Bureau,  and  a 
large  part  of  the  work  of  the  Bureau  will  consist  in  carrying  on  such 
correspondence  in  a more  satisfactory  way  than  has  heretofore  been 
possible. 


HOW  TO  USE  THE  BUREAU 

The  Montana  State  Bureau  of  Mines  and  Metallurgy  has  been 
established  for  the  use  of  anyone  interested  in  the  mining  industry 
of  Montana.  Its  success  will  depend  largely  upon  how  much  service 
it  is  asked  to  give.  The  Bureau  is  accessible  to  all,  and  is  located  at 
the  State  School  of  Mines,  in  Butte.  If  possible,  bring  your  problems 
to  the  Bureau  in  person;  if  not,  send  in  your  samples  and  questions  by 
mail  or  express.  All  samples  and  letters  should  be  addressed  to  the 
State  Bureau  of  Mines  and  Metallurgy,  Butte,  Montana. 

The  Bureau  is  reliable  and  is  well  equipped  to  carry  on  many 
different  kinds  of  investigations.  So  far  as  is  reasonable,  consistent 
with  reputable  practice,  and  within  the  limits  of  the  available  funds, 
all  problems  and  questions  will  receive  careful  consideration.  Ask  for 
the  reports  and  maps  of  the  Bureau,  and  use  them.  Do  not  go  ahead 
without  obtaining  the  available  information  concerning  the  mineral 
resources  of  Montana.  Let  the  Bureau  help  you  develop  the  mineral 
resources  and  increase  the  safety  and  surety  of  the  mining  industry. 


• — 8 — 


OWVEfisrr*  of  * tiDW'v 
AUG  25  1922 

UNIVERSITY  OF  MONTANA  BULLETIN 

BUREAU  OF  MINES  AND  METALLURGY  SERIES  NO.  2 


The  Montana  State  Bureau 

OF 

Mines  and  Metallurgy 


Directory 

Montana  Metal  and  Coal  Mines 


* rir  UijiMT  (|F  THE 

FEB-  2 6 1925 

DIVERSITY  OF  ILLINOIS 


STATE  SCHOOL  OF  MINES 
BUTTE,  MONTANA 
DECEMBER,  1919 


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STATE  BUREAU  OF  MINES  AND  METALLURGY 

STAFF 

CLAPP,  CHARLES  H.  - - - - - Director  and  Geology 

PhD.,  Massachusetts  Institute  of  Technology,  1910 

ADAMI,  ARTHUR  E.  - --  --  --  Mining  Engineer 

E.  M.,  Montana  State  School  of  Mines,  1907 

v ' PULSIFER.  H.  B,  - - - - - - - Metallurgy  and  Safety 

B.  S.,  Massachusetts  Institute  of  Technology,  1903; 

C. E.,  Armour  Institute  of  Technology,  1915; 

M.  S.,  University  of. Chicago,  1918. 


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FOREWORD 


The  purpose  of  this  bulletin  is  to  serve  as  a directory  of  all  the 
metal  and  coal  mining  companies  in  the  State  of  Montana.  Although 
every  effort  possible  by  correspondence  was  made  in  the  attempt  to 
get  information  on  every  mining  company  in  Montana,  it  is  possible 
that  some  companies  have  been  overlooked.  However,  it  is  believed 
that  this  bulletin  contains  the  names  of  most  of  the  operating  com- 
panies of  the  State,  together  with  some  general  information  on  each 
company,  and  that  the  bulletin  will  sefve  as  a valuable  reference  book 
for  those  interested  in  the  mining  industry.  This  bulletin  is  supple- 
mentary to  a report  on  the  various  mining  districts  of  Montana  which 
is  now  being  prepared  by  the  Geological  Department  of  the  State 
Bureau  of  Mines  and  Metallurgy. 


DIRECTORY  OF  MONTANA  OPERATING  METAL 

MINES 


ALICE  GOLD  AND  SILVER  MINING  CO.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
Officers:  Pres.,  John  D.  Ryan;  Secy-Treas.,  D.  B.  Hennessy,  42 
Broadway,  New  York,  N.  Y. 

Operating  Dept.:  Gen.  Mgr.,  John  Gillie,  Butte;  Asst.  Mgr.,  W.  B. 

Daly,  Butte;  Genl.  Supt.,  C.  L.  Berrien,  Butte. 

250  H.  P.  Steam  and  150  H.  P.  Electric. 

No.  of  men  employed:  125. 

Ores:  Complex  sulphides  of  silver,  zinc,  lead. 

Daily  output:  250  tons. 

Output  for  1918:  32,600  tons. 

Miscellaneous  Information:  Property  has  been  closed  down  most 
of  the  year  1919  on  account  of  poor  zinc  market. 


ALTA  MONTANA  MINING  CO.  Corbin. 

Location:  Colorado  Mining  District,  Jefferson  County. 

Officers:  Mgr.,  Raymond  Guyer,  218  Symons  Bldg.,  Spokane, 

Wash. 

Operating  Dept.:  Supt.,  R.  E.  Snow,  Corbin,  Mont. 

150  H.  P.  Electric. 

No.  of  men  employed:  12. 

Ores:  Lead-Silver. 

Miscellaneous  Information:  Past  two  years  has  been  spent  in 

opening  up  and  dewatering  old  works,  which  work  is  now 
about  complete.  A small  amount  of  ore  was  taken  out  in 
the  year  1918  by  leasers. 


AMERICAN  GEM  MINING  SYNDICATE.  Philipsburg. 

Location:  Flint  Creek  Mining  District,  Granite  County. 

Officers:  Pres.,  L.  M.  Rumsey;  Vice-Pres.,  C.  G.  Ewing;  Treas., 
L.  S.  Mitchell;  all  408  Olive  St.,  St.  Louis,  Mo. 

Operating  Dept.:  Gen’l  Mgr.,  C.  G.  Ewing,  Philipsburg. 

Water  power. 

No.  of  men  employed:  30. 

Ores:  Sapphire  placer. 


ANACONDA  COPPER  MINING  CO.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
Officers:  Pres.,  C.  F.  Kelley;  Vice-Pres.,  B.  B.  Thayer;  Secy, 
and  Treas.,  A.  H.  Melin;  Gen.  Auditor,  J.  T.  Roberts;  Asst. 
Treas.,  D.  B.  Hennessy;  all  42  Broadway,  New  York;  Asst. 
Secy.,  R.  D.  Cole,  Butte. 


Operating  Dept.;  Mgr.  of  Mines,  John  Gillie;  Asst.  Mgr.  of 
Mines,  W.  B.  Daly;  Gen.  Supt.  of  Mines,  C.  L.  Berrien;  Asst. 
Gen.  Supt.  of  Mines,  E.  M.  Noriss,  J.  J.  Carrigan,  and  J.  P. 
O’Neil;  Chief  Geologist,  Reno  H.  Sales. 

Electric,  Steam,  and  Compressed  Air. 

No.  men  employed:  9,000  to  11,000  (normally). 

Principal  ores:  Copper,  silver,  gold,  zinc,  and  manganese. 

Daily  output:  15,000  tons. 

1918  output:  4,925,022  tons. 

Miscellaneous  Information:  This  company  owns  1,168  acres  of 
mineral  claims  at  Butte,  including  all  the  property  formerly 
held  by  the  following  companies:  Boston  & Mont.,  Cons. 

C.  & S.  Mng.  Co.;  Butte  & Boston  Cons.  Mng.  Co.;  Red 
Metal  Mng.  Co.;  Washoe  Copper  Co.;  Parrot  Silver  and 
Copper  Co.;  Trenton  (formerly  Colorado)  Mng.  & Dev.  Co.; 
Big  Blackfoot  Lumber  Co.;  Diamond  Coal  & Coke  Co.; 
Original  Cons.  Mng.  Co.;  Colusa  Parrot  Mng.  & Sm.  Co.  This 
property  includes  the  following  mines  and  departments: 


Badger  State 
High  Ore 
Never  Sweat 
St.  Lawrence 


Mountain  View 
Tramway 
Silver  Bow 


Anaconda  Group. 


Moonlight 
Mountajn  Con 
Original 
Gray  Rock 


Bell-Diamond 

Anaconda 

Steward 

Belmont 


Boston  & Montana  Group. 

Pennsylvania  West  Colusa 

Leonard  Berkeley 

Tropic 


Zinc  Group  of  Mines 

Poulin  Nettie  Bonanza 

Emma  Alice  Lexington 

This  Company  also  operates  a gold  property  at  Southern  Cross,, 
fifteen  miles  west  of  Anaconda. 


Reduction  Departments. 

Washoe  Reduction  Works,  Anaconda. 

Frederick  Laist,  Manager. 

L.  V.  Bender,  Gen.  Supt. 

Boston  & Montana  Reduction  Works,  Great  Falls. 

James  O’Grady,  Manager. 

A.  E.  Wiggin,  Supt. 

Coal  Department. 

F.  W.  C.  Whyte,  Manager,  Anaconda. 

Thos.  Snedden,  Supt.,  Diamond  Coal  & Coke  Co.,  Diamondville,. 
Wyoming. 

Thos.  Good,  Supt.,  A.  C.  M.  Co.,  Coal  Dept.,  Washoe. 

C.  A.  Sederholm,  Supt.,  A.  C.  M.  Co.,  Coal  Dept.,  Sand  Coulee. 

Lumber  Department. 

Kenneth  Ross,  Manager,  Missoula. 

M.  M.  Ross,  Supt.,  St.  Regis. 


ALLIANCE  COPPER  COMPANY.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 

Officers:  Pres.,  Donald  Campbell,  Butte;  Vice-Pres.  and  Treas., 
J.  D.  Slemons,  Butte;  Sec’y.,  A.  T.  Morgan,  Butte. 

Mine  not  operating. 


—6— 


East  Helena. 


AMERICAN  SMELTING  AND  REFINING  CO. 

Location:  Lewis  and  Clark  County. 

Officers:  Pres.,  S.  Guggenheim;  Sec’y,  W.  E.  Merriss;  both  at  120 
Broadway,  New  York,  N.  Y. 

Operating  Dept.:  Mgr.,  C.  W.  Adams,  East  Helena;  Supt.,  R.  L. 

Strobel,  East  Helena. 

780  H.  P.  Electric. 

No.  of  men  employed:  300  to  400. 

Ores  smelted:  Gold,  silver,  and  lead. 

Daily  output:  75  tons  lead. 

1918  output:  27,564  tons  lead. 


ANGELICA  MINING  & DEVELOPMENT  CO.  Wickes. 

Location:  Colorado  Mining  District,  Jefferson  County. 

Officers:  Pres.,  C M.  d’Autremont,  Wickes;  Vice-Pres.,  Chas.  D. 
Horton,  Wickes;  Sec’y-Treas.,  C.  K.  Tibbetts,  Helena. 

Operating  Dept.:  Mgr.,  C.  M.  d’Autremont,  Wickes;  Supt.,  Chas. 
D.  Horton,  Wickes. 

60  H.  P.  Electric. 

No.  men  employed:  50  to  55. 

Ores:  Gold,  silver,  lead,  copper,  and  zinc  sulphides. 

Daily  output:  50  tons. 

1918  output:  12,583  tons. 

Miscellaneous  Information:  Developed  by  shaft  800  feet  deep  and 
adit  tunnel  4,500  feet  in  length  connecting  with  shaft.  Lead 
carbonate  ore  to  400  feet,  sulphide  zinc-lead  ore,  with  some 
copper,  to  800  feet.  Ore  shoots  100  to  300  feet  in  length,  3 to 
20  feet  wide.  Six  patented  claims,  109  acres.  Both  shipping 
and  concentrating  ore  being  developed. 


BALD  BUTTE  MINING  & MILLING  CO.  Marysville. 

Location:  Bald  Butte  Mining  District,  Lewis  and  Clark  County. 
Officers:  Pres.,  W.  A.  Stone,  Boston,  Mass.;  Sec’y-Treas.,  Wm. 
M.  Belcher,  Boston,  Mass. 

Operating  Dept.:  Supt.,  Geo.  W.  Padbury,  Marysville. 

35  H.  P.  Electric. 

No.  men  employed:  None  at  present. 

Daily  output:  None. 

1918  output:  760  tons  from  lessees. 


BALKAN  BUTTE  COPPER  MINING  CO.  Elk  Park. 

Location:  Elk  Park  Mining  District,  Jefferson  County. 

Officers:  Pres.,  Chas.  Steele,  Butte;  Sec’y  and  Treas.,  T.  Tomich, 
Butte. 

Operating  Dept.:  Gen.  Mgr.,  Chas.  Steele,  Butte;  Mgr.,  T.  To- 
mich, Butte. 

Not  operating  at  present. 


BARNES-KING  DEVELOPMENT  CO.  Kendall. 

Location:  North  Moccasin  Mining  District,  Fergus  County. 
Officers:  Pres.,  C.  W.  Goodale,  Butte;  Vice-Pres.,  A.  J.  Davis, 


—7— 


Butte;  Sec’y.,  John  E.  Corette,  Butte;  Treas.,  C.  C.  Swin- 
borne,  Butte. 

Operating  Dept.:  Gen.  Mgr.,  Geo.  T.  McGee,  Helena. 

Electric  power. 

No.  of  men  employed:  90. 

Ores:  Gold  and  silver. 

Daily  output:  100  tons. 

Miscellaneous  Information:  Also  owns  and  operates  the  Shannon 
Mine  and  the  Piegan-Gloster  Mine  and  Mill,  both  at  Marys- 
ville, Montana. 


BASIN  MINING  CO,  Philipsburg 

Location:  Flint  Creek  Mining  District,  Granite  County. 

Officers:  Pres.,  L.  W.  Rumsey,  Jr.,  408  Olive  St.,  St.  Louis,  Mo.; 
Vice-Pres.,  C.  G.  Ewing,  Philipsburg;  Treas.,  L.  S.  Mitchell. 
408  Olive  St.,  St.  Louis,  Mo. 

Operating  Dept.:  Gen’l  Mgr.,  C.  G.  Ewing,  Philipsburg. 

Water  power. 

No.  men  employed:  15. 

Ores:  Gold  placer. 


BEAVER  CREEK  MINING  CO.  Zortman 

Location:  Little  Rockies  Mining  District,  Philips  County. 
Officers:  Pres.,  Chas.  Whitcomb,  Helena;  Sec’y,  Notley  Thomp- 
son, Helena. 

Ores:  Gold. 

Miscellaneous  Information:  150,000  tons  of  ore  blocked  out,  but 
present  conditions  are  unfavorable  to  operation. 


BEN  HUR  MINING  CO.,  LTD.  Saltese. 

Location:  Denemora  Mining  District,  Mineral  County. 

Officers:  Pres.,  D.  S.  Dickson,  Quartz;  Vice-Pres.,  Frank  Bell, 
Saltese;  Sec’y-,  Chas.  J.  Luedke,  Saltese;  Treas.,  Chas.  A. 
Keating,  Wallace,  Idaho. 

Not  operating  at  present. 


BLUE  BIRD  MINING  CO.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
Officers:  Treas.,  Clarence  W.  McGuire,  89  State  St.,  Boston, 

Massachusetts. 

Not  operating  at  present. 


BLUE  VEIN  COPPER  MINING  CO.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
Officers:  Pres.,  F.  L.  Melcher,  Butte;  Vice-Pres.,  J.  F.  Charles, 
Butte;  Sec’y.,  Lewis  A.  Smith,  Butte. 

Has  not  been  operating  for  ten  years.  Owns  following  claims: 
Blue  Vein,  Blue  Vein  No.  2,  Ozone,  Myrahl,  North  Star,  Little 
Boulder,  Bunker  Hill,  Valentine,  and  Columbia. 


—8— 


BONANZA  BUTTE  MINING  CO.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
Officers:  Pres.,  John  Kenoffel,  17  S.  Main  St.,  Butte;  Sec’y-Treas., 
W.  R.  Youlden,  N.  Main  St.,  Butte. 

Ores:  Silver,  lead,  copper. 


BOSTON-BUTTE  COPPER  & ZINC  CO.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
Officers:  Pres,,  W.  W.  McDowell,  46  E.  Broadway,  Butte;  Sec’y- 
Treas.,  W.  E.  Reynolds,  46  E.  Broadway,  Butte;  Vice-Pres., 
F.  J.  Dorhofer,  Butte. 

Property  has  never  been  developed  and  is  not  operating. 


BROADWATER  COUNTY  MINING  CO.  Townsend. 

Location:  Park  Mining  District,  Broadwater  County. 

Officers:  Pres.,  James  J.  Fisher,  Townsend. 

Miscellaneous  Information:  Short  of  funds  and,  therefore,  not 

doing  any  mining  at  present. 


BUTTE  BACORN  COPPER  CO.  Butte 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
This  company  was  absorbed  by  the  Great  Butte  Copper  Co., 
which  see. 


BUTTE  COPPER  CO.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
Officers:  Pres.,  James  H.  Rowe,  Butte;  Vice-Pres.,  E.  F.  Lawlor, 
Boston,  Mass.;  Sec’y,  W.  M.  Hanson,  Butte. 

Operating  Dept.:  Supt.,  E.  L.  Ralston,  Butte. 

275  H.  -P.  Electric. 

No.  men  employed:  40. 

Ores:  Silver,  gold,  zinc,  and  lead. 

Daily  output:  None. 

1918  output:  1,760  tons. 

Miscellaneous  Information:  Development  work  only  being  done 
in  1919.  Mine  being  operated  by  Anselmo  Mining  Co. 


BUTTE  COPPER  CZAR  MINING  CO.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 

Officers:  Pres.,  C.  F.  Murphy,  Anaconda;  Treas.,  John  K.  Clax- 
ton,  Butte;  Sec’y,  L.  P.  Sanders,  Butte. 

Operating  Dept.;  Gen.  Mgr.,  E.  C.  Meiklejohn,  Butte. 

Electric  power. 

No.  men  employed:  20. 

Ores:  Copper. 

Miscellaneous  Information:  This  mine  has  not  been  operated 
since  July,  1918,  but  plans  are  being  made  to  reopen  work 
and  operations  within  the  next  ninety  days. 

—9— 


BUTTE  COPPER  KING  MINING  CO.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 

Officers:  Pres.,  Chas  E.  Beebe,  Butte;  Sec’y-Treas.,  A.  P.  Hen- 
ningsen,  Portland,  Ore. 

This  company  owns  property  consisting  of  three  undeveloped 
claims  located  north  of  the  Butte  Water  Company’s  Reser- 
voir in  Butte. 


BUTTE  COPPER  & ZINC  CO.  Polaris. 

Location:  Polaris  Mining  District,  Beaverhead  County. 

Officers:  Pres.,  A.  J.  Seligman,  61  Broadway,  New  York;  Sec’y- 
Treas.,  D.  J.  Fagensen,  61  Broadway,  New  York. 

Operating  Dept.:  Gen.  Mgr.,  Glenn  Anderson,  46  E.  Broadway, 
Butte. 

200  H.  P.  Steam. 

Ores:  Silver  and  copper. 


BUTTE  & GREAT  FALLS  MINING  CO.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 

Officers:  Pres.,  E.  Bryant  Crump,  Lexington,  Ky.;  Sec’y-Treas., 
Allen  Pierse,  Great  Falls. 

Operating  Dept.:  Gen.  Mgr.,  R.  M.  Green,  Butte. 

Electric  Power. 

No.  men  employed:  20. 

Ores:  Copper  and  silver. 

Miscellaneous  Information:  This  mine  has  not  operated  in  the 
past  two  years,  but  a plan  for  refinancing  same  is  now  under 
way.  Efforts  are  being  made  to  induce  Eastern  capital  to 
finance  further  development  work  at  the  mine.  The  pros- 
pects are  good  for  an  early  reopening  of  development  work. 
Mr.  R.  M.  Green,  the  General  Manager,  above  mentioned,  died 
some  time  ago  and  his  place  remains  vacant.  It  will  be  filled 
at  an  early  date,  as  soon  as  financial  arrangements  are  com- 
pleted. 


BUTTE  HILL  COPPER  MINING  CO.  Walkerville. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
Officers:  Pres.,  Maurice  Essenberg,  New  York,  N.  Y.;  Sec’y- 

Treas.,  H.  A.  Frank,  Butte. 

Not  operating  at  present. 


BUTTE  & LONDON  COPPER  DEVELOPMENT  CO.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
Officers:  Pres.,  W.  W.  McDowell,  Butte;  Vice-Pres.,  John  D. 
Plaines,  Butte;  Sec’y.,  W.  E.  Reynolds,  Butte;  Treas.,  E.  S. 
Passmore,  Butte. 

Property  has  been  closed  down  for  three  years. 


BUTTE  MAIN  RANGE  COPPER  MINING  CO.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
This  property,  consisting  of  38  acres,  was  sold  to  the  Tuolumne 
Copper  Mining  Company  in  1918. 


-10- 


BUTTE-MILWAUKEE  MINING  CO.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
This  property,  which  is  under  control  of  the  Butte  & Superior 
Mining  Company,  was  never  a producer,  and  has  been  closed 
down  for  several  years. 


BUTTE-NEW  YORK  COPPER  CO.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
This  property  is  controlled  by  the  Butte  & Superior  Mining  Com- 
pany, but  no  operations  have  been  conducted  for  several  years. 


BUTTE  & SUPERIOR  MINING  CO.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
Officers:  Pres.,  D.  C.  Jackling;  Sec’y,  A.  J.  Ronazhan;  Treas., 
C.  W.  Peters;  all  25  Broad  St.,  New  York. 

Operating  Dept.:  Gen.  Mgr.,  J.  L.  Bruce,  Butte;  Asst.  Mgr.,  Chas. 
Bocking,  Butte;  Mine  Supt.,  A.  B.  McLeod,  Butte;  Mill  Supt., 
E.  V.  Daveler,  Butte. 

7,500  H.  P.  steam,  electric,  and  compressed  air. 

No.  men  employed:  1,200  daily. 

Ores:  Zinc,  lead,  silver. 

Daily  Output:  1,400  tons'. 

1918  output:  469,079  tons. 


BUTTE  & VIPOND  GOLD  MINING  & MILLING  CO.  Melrose. 

Location:  Vipond  Mining  District,  16  miles  northwest  of  Melrose, 
in  Beaverhead  County. 

Officers:  Pres.,  James  M.  Hinkle,  Butte;  Vice-Pres.,  Thos  P. 
Manley,  Butte;  Treas.,  William  Worth,  Butte;  Sec’y,  W.  E. 
Carroll,  Butte. 

Miscellaneous  Information:  This  property,  which  is  a gold,  silver, 
lead  property,  is  developed  by  a 740-foot  tunnel  tapping  a 
vertical  shaft  at  200  feet.  Work  of  draining  was  finished  in 
1919.  The  property  consists  of  five  claims,  formerly  known  as 
“Queen  of  the  Hills,”  but  now  known  as  “Martin,”  “Jenkins,” 
“Shady,”  “Little  Victor,”  and  “Vipond  Park”  Lodes.  Not 
operating  at  present. 


BUTTE  & WILLOW  CREEK  MINING  CO.  Pony. 

Location:  Mineral  Hill  Mining  District,  4 miles  from  Pony,  in 
Madison  County. 

Officers:  Pres.,  P.  T.  McDermott,  Helena;  Vice-Pres.,  James  E. 

Redmond,  Butte;  Sec’y.,  James  Naughten,  Butte. 

50  H.  P.  water  and  steam. 

Ores:  Iron  pyrites,  gold  and  silver. 

Not  operating  since  1914. 


CAPE  NOME  COPPER  MINING  CO.  Clinton. 

Location:  Wallace  Mining  District,  Missoula  County. 

—11— 


Officers:  Pres.,  E.  Donlan,  Missoula;  Sec’y-Treas.,  H.  T.  Wil- 
kinson, Missoula. 

120  H.  P.  Steam — two  60  H.  P.  boilers. 

Ores:  Copper  and  silver. 

Miscellaneous  Information:  This  property  has  4,600  feet  of  de- 
velopment work,  including  a double  compartment  shaft  500 
feet  deep,  with  drifts  on  the  100,  300  and  500-foot  levels. 
Property  not  operating  at  present. 


CASCADE  SILVER  MINES  AND  MILLS.  Neihart. 

Location:  Montana  Mining  District,  Cascade  County. 

Officers:  Pres.,  Geo.  H.  Brabrook,  Neihart;  Vice-Pres.,  Lowndes 
Maury,  Butte;  Sec’y.,  Wm.  R.  McLure,  Philipsburg;  Treas., 
W.  P.  Wren,  Great  Falls. 

Operating  Dept.:  Gen  Mgr.,  Geo.  Hale  Brabrook,  Neihart;  Supt., 
Thos.  Westgard,  Neihart. 

Electric  power. 

No',  men  employed:  200. 

Ores:  Silver. 

Daily  output:  200  tons. 

1918  output:  2,500  tons. 

COLUSA  LEONARD  EXTENSION  COPPER  CO.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
This  property,  consisting  of  42  acres,  was  sold  to  the  Tuolumne 
Copper  Mining  Company  in  1918. 


COLUSA-PARROT  MINING  & SMELTING  CO.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
Officers:  Pres.,  W.  A.  Clark,  Butte;  Vice-Pres.,  W;  C.  Siderfin, 
Butte;  Sec’y,  W.  C.  M.essias,  Butte. 

25  H.  P.  Electric. 

No.  men  employed:  20. 

Daily  output:  1,300  tons. 

1918  output:  387,073  dry  tons. 

Ores:  Working  copper  tailings  at  Butte  Reduction  Works,  Butte. 
Miscellaneous  Information:  Tailings  are  shipped  to  Timber  Butte 
Milling  Co.  for  concentrating,  and  concentrates  shipped  to 
Anaconda  Copper  Mining  Company’s  Smelter,  Anaconda. 


COMBINATION  OPERATING  COMPANY.  Philipsburg. 

•Location:  Flint  Creek  Mining  District,  Granite  County. 

Officers:  Company  not  organized  at  this  date  and  officers  not 
officially  appointed.  However,  Geo.  C.  Crangle,  Ray  E. 
Tower,  Edward  Roach,  Harry  T.  Lewis,  Marcus  L.  Hurley 
are  the  owners  and  operators. 

60  H.  P.  Steam. 

No.  men  employed:  At  present,  about  ten  engaged  in  remodeling 
mill.  Operating  force  will  be  about  25. 

Ores:  Silver  and  copper  (subordinate:  lead  and  gold). 

Daily  output:  100  tons. 

1918  output:  None. 

Miscellaneous  Information:  Remodeling  chloridizing  and  leaching 
plant  to  treat  old  mill  tailings. 

—12— 


CONREY  PLACER  MINING  CO.  Ruby. 

Location:  Pres.,  Chas.  F.  Adams,  Boston,  Mass.;  Vice-Pres. 

and  Consulting  Engineer,  Hennen  Jennings,  Washington,  D. 
C.;  Sec’y  and  Treas.,  F.  F.  Stanley,  Boston,  Mass. 

Operating  Dept.:  Business  Mgr.,  G.  H.  Edmunds*,  Ruby;  Dredge 
Supt.,  O.  O.  Sweeny,  Ruby. 

1,475  H.  P.  Electric. 

No.  men  employed:  55  (average). 

Ores:  Placer  gold  and  silver. 

Daily  output:  15,000  cu.  yds. 

1918  output:  3,350,000  cu.  yds. 

Miscellaneous  Information:  No.  1 dredge  operated  full  year  with 
7y2  cu.  ft.  buckets;  No.  2 dredge  operated  4 months  with  iy2 
cu.  ft.  buckets,  and  No.  4 dredge  operated  full  year  with  17 
cu.  ft.  buckets. 


CRYSTAL  COPPER  COMPANY.  Butte  and  Basin. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County; 
Cataract  Mining  District,  Jefferson  County. 

Officers:  Pres.,  B.  S.  Parker,  31  Milk  St.,  Boston,  Mass.;  Sec’y, 
Eugene  H.  Walker,  31  Milk  St.,  Boston,  Mass. 

Operating  Dept.:  Gen.  Mgr.,  Goldsmith  Mine,  Butte,  W.  D.  Gib- 
son, Butte;  Mgr.  and  Lessee,  Crystal  Mine,  Basin,  A.  C. 
Ray,  Basin. 

100  H.  P.  Electric. 

Ores:  Crystal  Mine,  Basin,  copper  and  silver;  Goldsmith  Mine, 
Butte,  silver  and  gold. 

Miscellaneous  Information:  Both  these  mines  are  in  the  develop- 
ment stage.  The  Crystal  Mine  is  operated  through  two  tun- 
nels, each  over  1,200  feet  long.  The  Goldsmith  Mine  is  being 
operated  from  the  500  and  600-foot  levels  by  a main  shaft. 
Ore  is  shipped  to  the  Washoe  Smelter  at  Anaconda,  and  to 
the  American  Smelting  & Refining  Company  at  East  Helena. 


DAVIS-DALY  COPPER  CO.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
Officers:  Pres..  H.  M.  Burton;  Sec’y-Treas.,  C.  G.  Schirmer; 

both  Boston,  Mass. 

Operating  Dept.:  Mgr.,  C.  L.  Bruce,  Butte;  Supt.,  D.  J.  McGrath, 
Butte;  Foreman,  James  White,  Butte. 

1300  H.  P.  Electric. 

No.  men  employed:  400. 

Ores:  Copper  and  silver. 

Daily  output:  300  tons. 

1918  output:  66,158  tons. 


EAST  BUTTE  COPPER  MINING  CO.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
Officers:  Pres.,  Robt.  H.  Gross;  Sec’y,  Wm.  P.  Everts;  Treas., 
Frank  P.  Son;  all  of  Boston,  Mass. 

Operating  Dept.:  Gen.  Mgr.,  Oscar  Rohn,  Butte. 

Electric  power. 

No.  men  employed:  800. 

Ores:  Copper,  silver,  gold. 


-13— 


Miscellaneous  Information:  This  company  operates  the  proper- 
ties of  the  Pittsmont  Copper  Company  under  an  agreement 
entered  into  on  April  8,  1909. 


EAST  BUTTE  EXTENSION  COPPER  MINING  CO.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
Officers:  Pres.,  Chas.  J.  Schatzlein,  Butte;  Vice-Pres.,  Philip  A. 
Breen,  Butte. 

Operating  Dept.:  Gen.  Mgr.,  Frank  H.  Cooney,  Butte. 

Ores:  Copper  and  Silver. 

Not  operating  at  present. 


ECONOMY  MINES  CO.  Helena. 

Location:  Lewis  and  Clark  County. 

Officers:  Pres.,  J.  Kessner,  Chicago,  111.;  Vice-Pres.,  S.  Rosen- 
field,  Helena;  Sec’y,  J.  Rosenfield,  Helena. 

Operating  Dept.:  Mgrs.,  Rosenfield  Brothers,  Helena. 

200  H.  P.  Electric. 

No.  men  employed:  30. 

Ores:  Gold  and  silver. 

Miscellaneous  Information:  Although  development  work  is  being 
done  on  the  property,  during  the  last  year  a 100-ton  concen- 
trating plant  has  been  erected. 


ELK  GOLD  MINING  COMPANY.  Deer  Lodge. 

Location:  Racetrack  Creek  Mining  District,  10  miles  S.  E.  of 

Deer  Lodge,  Powell  County. 

Officers:  Pres.,  C.  E.  Aspling,  Deer  Lodge;  Trustees,  I.  S.  Eldred 
and  J.  E.  Nevill,  Deer  Lodge. 

30  H.  P.  Steam. 

No.  men  employed:  4. 

Ores:  Gold,  silver,  and  copper. 

Miscellaneous  Information:  Recently  began  sinking  shaft. 


ELM  ORLU  MINING  CO.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
Officers:  Pres.,  W.  A.  Clark,  Jr.,  Butte;  Sec’y-Treas.,  W.  D. 

Mangam,  Butte. 

Operating  Dept.:  Gen.  Mgr.,  W.  N.  Rossberg,  Butte. 

3,000  H.  P.  Electric. 

No.  men  employed:  500. 

Ores:  Copper,  zinc,  and  silver. 

Daily  output:  600  tons. 

1918  output:  208,651  dry  tons  combined  zinc  and  copper  ores. 


GRANITE-BIMETALLIC  CONSOLIDATED  MINING  CO. 

Philipsburg. 

Location:  Flint  Creek  Mining  District,  Granite  County. 

Officers:  Pres.,  John  P.  Meyer;  1st  Vice-Pres.,  Edward  S.  Orr; 
2nd  Vice-Pres.,  L.  M.  Rumsey;  all  of  St.  Louis,  Mo. 


Operating  Dept.:  Acting  Supt.,  R.  S.  Blitz,  Philipsburg. 

No.  men  employed:  18;  96  leasers. 

Ores:  Silver. 

Daily  output:  30  tons. 

1918  output:  27,429  tons. 

Miscellaneous  Information:  3,000  acres  of  ground.  In  early  days 
this  property  was  a large  producer,  but  is  now  being  entirely 
worked  by  leasers. 


GLENGARRY  MINING  CO.  Cooke  City. 

Location:  New  World  Mining  District,  Park  County. 

Officers:  Pres.,  J.  T.  Hamilton,  Miles  City;  Vice-Pres.,  Charles 
Daly,  Cooke  City;  Secy  and  Treas.,  C.  H.  Loud,  Miles  City. 

Operating  Dept.:  Mgr.,  Charles  Daly,  Cooke  City. 

Hand  Power. 

No.  men  employed:  8. 

Ores:  Gold,  silver,  and  copper. 

Miscellaneous  Information:  Have  just  started  to  operate  these 

mines,  which  have  been  idle  for  a number  of  years.  Expect 
to  get  10  cars  marketed  this  season.  This  company  is  suc- 
cessor to  the  Montana  Scotch  Bonnet  Copper  and  Gold 
Mining  Co. 


GOLDEN  CURRY  LEASING  CO.  Elkhorn. 

Location:  Elkhorn  Mining  District,  Beaverhead  County. 

Officers:  Mgr.,  M.  I.  Lydig,  Elkhorn. 

30  H.  P.  Electric. 

No.  men  employed:  16. 

Ores:  Iron,  gold. 

Daily  output:  30  tons. 

Miscellaneous  Information:  Iron  is  mined  for  flux.  Shipping  to 
American  Smelting  & Refining  Company. 


GREAT  BUTTE  COPPER  CO.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
Officers:  Pres.,  F.  W.  Bacorn,  Butte;  Treas.,  Charles  Hyde,  331 
Fourth  Ave.,  Pittsburg,  Pa. 

Steam  and  electric  power. 

No.  men  employed:  Average  25. 

Ores:  Copper  and  zinc. 

Miscellaneous  Information:  Doing  extension  work  only. 

HUGO  GOLD  AND  COPPER  MINING  CO.  Saltese. 

Location:  Denemora  Mining  District,  Mineral  County. 

Officers:  Pres.,  R.  W.  Seideman,  Saltese;  Vice-Pres.,  W.  W. 

Woods,  Wallace,  Idaho. 

Water  power. 

Ores:  Gold  and  copper. 


INGERSOLL  MINING  COMPANY.  Neihart. 

Location:  Montana  Mining  District,  Cascade  County. 

Officers:  Pres.,  Allen  Pierse,  Great  Falls;  Sec’y-Treas.,  E.  A. 
Shaw,  Great  Falls. 


—15— 


Ores:  Silver  and  lead. 

Miscellaneous  Information:  Property  has  been  idle  for  several 

years,  but  arrangements  are  now  being  made  to  resume 
operations. 


INTER  MOUNTAIN  MINING  CO.  Iron  Mountain. 

Location:  Iron  Mountain  Mining  District,  Mineral  County. 
Officers:  Pres.,  E.  Evans,  Post  St.,  Spokane,  Wash.;  Vice-Pres., 
R.  G.  McIntosh,  Spokane,  Wash.;  Sec’y-Treas.,  E.  C.  Danfer, 
Spokane,  Wash. 

Operating  Dept.:  Supt.,  P.  L.  Hoffman,  Iron  Mountain. 

450  H.  P.  Electric,  and  250  H.  P.  Water. 

No.  men  employed:  75  (normally). 

Ores:  Copper,  carrying  some  gold  and  silver. 

Daily  output:  150  tons. 

Miscellaneous  Information:  At  present  only  prospecting  and  de- 
veloping, using  18  men. 


JARDINE  GOLD  MINING  & MILLING  CO.  Jardine. 

Location:  Sheepeater  Mining  District,  Park  County. 

Officers:  Pres,  and  Treas.,  W.  S.  Hunnewell,  Drummond;  Vice- 
Pres.  and  Gen.  Mgr.,  H.  C.  Bacorn,  Jardine. 

300  H.  P.  Electric. 

No.  men  employed:  50. 

Ores:  Gold  and  tungsten. 

Daily  output:  30  tons  at  present. 

Miscellaneous  Information:  40-stamp  mill  put  in  operation  in  1919, 
handling  about  150  tons  of  ore  per  day. 


JIB  MINING  CO.  Basin. 

Location:  Cataract  Mining  District,  Jefferson  County. 

Officers:  Pres.,  A.  E.  Spriggs,  Helena;  Vice-Pres.,  M.  L.  Hewett, 
Basin;  Sec’y*>  Sol  Genzberger,  Butte. 

Operating  Dept.:  Mgr.,  M.  L.  Hewett,  Basin;  Supt.,  R.  Brinlori, 
Basin;  Asst.  Supt.,  Arthur  Louiselle,  Basin. 


KENDALL  LEASING  CO.  Kendall. 

Location:  North  Moccasin  Mining  District,  Fergus  County. 
Operating  Dept.:  Mgr.,  A.  B.  Fox,  Kendall;  Foreman,  Frank 

Bryant,  Kendall. 

175  H.  P.  Electric. 

No.  men  employed:  15. 

Ores:  Gold. 

Daily  output:  Not  regular. 

1918  output:  7,152  tons. 

Miscellaneous  Information:  The  Kendall  Mine  is  owned  by  the 
Barnes-King  Development  Co.,  successors  to  the  Kendall  Gold 
Mining  Co.,  and  is  under  lease  to  A.  B.  Fox  and  S.  D.  Whipple, 
working  under  the  above  name. 

—16— 


Saltese. 


LAST  CHANCE  MINING  CO. 

Location:  Denemora  Mining  District,  Mineral  County. 
Officers:  Pres,  and  Mgr.,  Geo.  Champagne,  Saltese. 

No.  men  employed:  2. 

Ores:  Silver,  lead  and  copper. 

Miscellaneous  Information:  Doing  development  work  only. 


LEGAL  TENDER  CONSOLIDATED  MINES  CO.  Clancy. 

Location:  Lump  Gulch  Mining  Dist.,  Jefferson  County. 

Officers:  Pres.,  H.  A.  Gallwey,  Butte;  Sec’y.  J-  H.  Heilbronner, 
Butte;  Treas.,  Wm.  Stussy,  Butte. 

Operating  Dept.:  Supt.,  D.  J.  Courtney,  Clancy;  Foreman,  Wm. 

Murrey,  Clancy. 

75  H.  P.  Electric. 

No.  men  employed:  25. 

Ores:  Silver. 

Output:  Irregular. 

Miscellaneous  Information:  Mine  producing  an  average  of  two 
cars  a month,  and  extensive  development  work  being  done. 


LEVIATHAN  GOLD  MINING  CO.  Pony. 

Location:  Mammoth  Mining  District,  Madison  County. 

Officers:  Pres.,  Chas.  E.  Morris,  Pony;  Vice-Pres.,  J.  L.  Temple- 
man,  Butte;  Treas.,  Wm.  C.  Morris,  Pony;  Sec’y,  James  A. 
Flint,  Pony. 

Operating  Dept.:  Lessee,  Ben  W.  Wilson,  Jefferson  Island. 

Ores:  Copper,  gold,  and  silver. 

Miscellaneous  Information:  For  past  two  years  this  property  has 
been  under  contract  for  sale  and  lease  to  B.  W.  Wilson.  Ma- 
tured payments  have  been  made,  with  the  probability  of  com- 
pletion, which  will  put  the  above  company  out  of  business. 


LITTLE  NELL  MINE.  Clancy. 

Location:  Lump  Gulch  Mining  District,  Jefferson  Count. 

Officers  (Operating  Dept.) : Gen.  Mgr.,  Stanly  A.  Easton,  Kel- 
logg, Idaho;  Mgr.,  H.  H.  Mayer,  East  Helena;  Foreman,  T. 
Brownlow,  Clancy. 

70  H.  P.  Steam. 

No.  men  employed:  10. 

Ores:  Silver,  lead,  zinc. 

Miscellaneous  Information:  At  present  doing  development  work 
only. 


LIVERPOOL  SILVER  MINES  CO.  Helena. 

Location:  Spring  Hill  Mining  District,  Lewis  and  Clark  County. 
Officers:  Pres.,  John  W.  Brien,  Essex,  Ontario;  Sec’y.,  W.  G. 
Burns,  27  State  St.,  Boston,  Mass.;  Treas.,  James  E.  Simpson, 
27  State  St.,  Boston,  Mass. 

Operating  Dept.:  Mgrs.,  Frank  Eichelberger  and  Chas  E.  Fry- 
berger,  Helena. 

250  H.  P.  Electric. 


17— 


No.  men  employed:  21. 

Ores:  Silver-lead  sulphides. 

Miscellaneous  Information:  Opened  old  levels  and  installed  new 
headframe  and  hoist  in  1919;  hoisting  steadily  Dec.  1,  1919. 


LUKENS  HAZEL  MINING  CO.  Libby. 

Location:  Snow  Shoe  Mining  District,  Lincoln  County. 

Officers:  Pres,  and  Gen.  Mgr.,  C.  Ed.  Lukins,  Libby;  Sec’y  and 
Treas.,  Wm.  Jennison,  Libby. 

Miscellaneous  Information:  At  present  this  company  is  not  work- 
ing its  mine,  but  is  engaged  in  building  a concentrator  and 
power  plant,  which  will  use  600  H.  P.  electric  power. 


MAGINNIS  MINE.  Maiden. 

Location:  Giltedge  Mining  District,  Fergus  County. 

Lessee:  W.  A.  Young,  Maiden. 

60  H.  P.  Steam  and  gasoline  power. 

No.  men  employed:  10. 

Ores:  Gold  and  silves,  with  more  or  less  lead  and  copper. 

1918  output:  About  150  tons. 

Miscellaneous  Information:  What  is  known  as  the  Maginnis 

Mine  is  owned  by  A.  M.  Holter,  Helena,  one-fourth  interest, 
and  Dartmouth  Land  Company,  Great  Falls,  three-fourths 
interest. 


W.  D.  MARLOW.  Livingston. 

Location:  Park  County. 

Officers  (Operating  Dept.):  Gen.  Mgr.,  W.  E.  Renshaw,  Idaho 
Springs,  Colo.;  Supt.,  O.  V.  Miller,  Cooke  City,  Mont. 

25  H.  P.  Gasoline. 

No.  men  employed:  7. 

Ores:  Gold,  silver,  lead. 

1918  output:  200  tons. 

Miscellaneous  Information:  Just  beginning  daily  production;  mine 
has  been  idle  for  several  years. 


MONTANA  CONSOLIDATED  COPPER  CO.  Comet. 

Location:  Cataract  Mining  District,  Jefferson  County. 

Officers:  Pres,  J.  V.  Allen;  Treas,  T.  F.  Lee;  both  51  Wall  St, 
New  York. 

Operating  Dept.:  Gen.  Mgr,  H.  J.  McKenzie,  Basin. 

300  H.  P.  Electric. 

No.  men  employed:  10  (at  present). 

Ores:  Silver,  gold,  copper,  zinc,  lead. 

Daily  output:  40  tons. 

Miscellaneous  Information:  Mine  closed  down  in  August,  1919, 
to  allow  for  reorganization  preparatory  to  starting  large  scale 
mining  and  milling.  Crew  of  10  men  keeping  mine  unwatered 
and  in  good  shape. 


—18— 


Garnet. 


MITCHELL  & MUSSIGBROD,  INC. 

Location:  First  Chance  Mining  District,  Granite  County. 
Officers:  Pres.,  Louis  Mussigbrod,  Garnet;  Vice-Pres.,  J.  Moken- 
land,  Warm  Springs;  Sec’y,  Albert  Galen,  Helena. 

Leaser:  Louis  Mussigbrod. 

60  H.  P.  Steam. 

No.  men  employed:  18. 

Ores:  Sulphide  ores,  gold,  and  silver. 

Miscellaneous  Information:  Installed  K.  & K.  flotation  plant  in 
1913,  and  started  operation  in  February,  1919. 


MONTANA  OREWAY  MINING  DISTRICT.  Jackson. 

Location:  Big  Hole  Mining  District,  Beaverhead  County. 
Officers:  Pres,  and  Mgr.,  Wm.  P.  Jahnke,  Wisdom;  Sec’y.,  F.  W. 

Scott,  Chicago,  111.;  Treas.,  John  D.  Rankin,  Chicago,  111. 

35  H.  P.  Steam  and  compressed  air. 

No.  men  employed:  15. 

Ores:  Copper,  silver,  lead,  gold. 

Miscellaneous  Information:  Two  carloads  shipped  for  demon- 

stration purposes.  Company  expects  to  erect  concentrator. 


MONTANA  RADERSBURG  MINING  CO.  Radersburg. 

Location:  Cedar  Plain  Mining  District,  Broadwater  County. 
Officers:  Pres.,  A.  E.  Spriggs,  Helena;  Sec’y,  B.  E.  Matthews, 
Helena;  Treas.,  C.  A.  Whipple,  Helena. 

Operating  Dept.:  Mgr.,  A.  E.  Spriggs,  Helena. 

25  H.  P.  Gasoline. 

No.  men  employed:  4. 

Ores:  Lead,  silver. 

1918  output:  200  tons. 


MOULTON  MINING  COMPANY.  Walkerville. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
Officers:  Pres.,  W.  A.  Clark,  Butte;  Vice-Pres.,  W.  C.  Siderfin, 
Butte;  Sec’y,  J.  C.  Phillips,  Butte. 

219  H.  P.  Electric. 

No.  men  employed:  20. 

Ores:  Copper  and  silver,  zinc  and  lead. 

Daily  output:  40  tons. 

1918  output:  3,000  tons. 

Miscellaneous  Information:  Principally  development  work  being 
done. 


NORTH  BUTTE  MINING  COMPANY.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
Officers:  Pres.,  Robert  Linton,  New  York;  Vice-Pres.,  Joseph 

B.  Cotton,  New  York;  Sec’y-Treas.,  F.  R.  Kennedv,  New 
York,  N.  Y. 

Operating  Dept.:  Gen.  Mgr.,  N.  B.  Braly,  Butte;  Supt.,  L.  D. 

Frink,  Butte. 

3,600  H.  P.  Electric  and  steam. 


—19— 


No.  men  employed:  850. 

Ores:  Copper  and  silver. 

Daily  output:  880  tons. 

1918  output:  465,389  tons. 

Miscellaneous  Information:  At  present  operating  at  about  60  per 
cent,  of  full  capacity. 


PATTEN  MINING  CO.  Philipsburg. 

Location:  Flint  Creek  Mining  District,  Granite  County. 

Officers:  Pres.,  A.  J.  Johnston,  Butte;  Vice-Pres.,  Earle  B.  Pat- 
ten, Philipsburg;  Sec’y-Treas.,  J.  K.  Heslet,  Butte. 
Miscellaneous  Information:  Not  operating  at  present. 


PHILIPSBURG  MINING  COMPANY.  Philipsburg. 

Location:  Flint  Creek  Mining  District,  Granite  County. 

Officers:  Pres.,  John  P.  Meyer,  St.  Louis,  Mo.;  Vice-Pres.,  John 
H.  Dieckman,  St.  Louis,  Mo.;  Treas.,  Firmin  D.  Fusz,  St. 
Louis,  Mo. 

Operating  Dept.:  Supt.,  R.  S.  Blitz,  Philipsburg;  Asst.  Supt.,  A.  E. 

Fritzberg,  Philipsburg. 

700  H.  P.  Electric. 

No.  men  employed:  225. 

Ores:  Manganese  dioxide,  silver,  and  copper. 

Daily  output:  75  tons. 

1918  output:  42,480  tons. 

Miscellaneous  Information:  Operating  Algonquin,  Bryant,  True 
Fissure,  Horton,  and  Hope  Mines,  and  300-ton  concentrating 
mill. 


PIEGAN-GLOSTER  MINE  (See  Barnes-King  Development  Co.). 


PITT  COPPER  MINING  CO.  Keystone. 

Location:  Mineral  County. 

Officers:  Pres.,  John  A.  Lathwood,  Pittsburg,  Pa.;  Vice-Pres., 

W.  S.  M'arkley,  Pittsburg;  Sec’y,  W.  D.  Brewer,  Pittsburg; 
Treas.,  J.  II.  B.  Phillips,  Pittsburg. 

Operating  Dept.:  Supt.,  L.  C.  McHeffey,  Keystone,  Mont. 

80  H.  P.  Gasoline. 

Ores:  Copper,  lead,  silver,  gold,  zinc. 

Daily  output:  Mill  capacity,  100  tons. 

1918  output:  150  tons  concentrates;  450  tons  crude  ore. 
Miscellaneous  Information:  Not  operating  at  present. 


PITTSMONT  COPPER  COMPANY.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
Officers:  Pres.,  Robt.  H.  Gross,  Boston,  Mass;  Vice-Pres.,  James 
H.  Reed,  Pittsburg,  Pa.;  Sec’y-Treas.,  F.  Ward  Paine,  Hough- 
ton, Mich. 

Operating  Dept.:  Gen.  Mgr.,  Oscar  Rohn,  Butte. 


—20— 


2000  H.  P.  Electric;  2000  H.  P.  Steam. 

No.  men  employed:  500. 

Daily  output:  500  tons. 

1918  output:  185,000  tons. 

Miscellaneous  Information:  Properties  of  this  company  are  oper- 
ated by  the  East  Butte  Copper  Mining  Company  under  an 
agreement  entered  into  April  8th,  1909. 


POTOMAC  COPPER  COMPANY.  Potomac. 

Location:  Missoula  County. 

Officers:  Pres.,  W.  P.  Jahn,  Milwaukee,  Wis.;  Vice-Pres.,  Paul 
A.  Gow,  Butte;  Treas.,  Geo.  E.  Palmer,  Butte;  Sec’y,  J-  J. 
Harrington,  Butte. 

Operating  Dept.:  Supt.,  W.  I.  Higgins,  Potomac. 

85  H.  P.  Steam. 

No.  men  employed:  30. 

Ores:  Copper  and  gold. 

Miscellaneous  Information:  Development  work  only. 


REVENUE  MINES.  Norris. 

Location:  Lower  Hot  Spring  Mining  District,  Madison  County. 
Officers:  De  West  Candee  and  Howard  S.  Candee;  both  43  Ex- 
change Place,  New  York. 

Trustee:  G.  D.  B.  Turner,  Norris,  Mont. 

Steam  Power  (installing  250  H.  P.  Electric). 

No.  men  employed:  18. 

Ores:  Gold. 


SCRATCH  AWL  MINING  & DEVELOPMENT  CO.  Philipsburg. 

Location:  Flint  Creek  Mining  District,  Granite  County. 

Officers:  Pres.,  J.  R.  Moyle,  Butte;  Vice-Pres.,  T.  Tomich,  Butte; 

Sec’y-Treas.,  W.  N.  Waugh,  Butte. 

Operating  Dept.:  Gen.  Mgr.,  E.  F.  Shields,  Philipsburg. 

125  H.  P.  Electric. 

No.  men  employed:  16. 

Ores:  Silver,  lead,  copper,  zinc,  and  manganese. 

Daily  output:  5 tons. 


SHANNON  MINE  (See  Barnes-King  Development  Company). 


SILVER  CABLE  MINING  COMPANY.  Missoula. 

Location:  Coeur  d’Alene  Mining  District,  Missoula  County. 
Officers:  Pres,  and  Gen.  Mgr.,  Jas.  D.  Corbett,  Missoula;  Vice- 
Pres.,  J.  W.  Kennedy,  Missoula;  Sec’y-Treas.,  Carl  C.  Mott, 
Missoula. 

Hand  power. 

No  men  employed:  7. 

Ores:  Lead-zinc,  with  silver. 

Miscellaneous  Information:  Development  work  only. 


—21— 


SILVER  TIP  MINING  CO.  Troy. 

Location:  Lincoln  County. 

Officers:  Pres.,  J.  P.  Schmuck;  Vice-Pres.,  Harry  Rosenkop; 

Sec’y,  R.  H.  Hutchin;  all  310  Hyde  Blk.,  Spokane,  Wash. 

Ores:  Zinc,  lead,  silver. 

Miscellaneous  Information:  Not  operating. 


SNOW  STORM  MINES  CONSOLIDATED.  Troy. 

Location:  Lincoln  County. 

Officers:  Pres,  and  Gen.  Mgr.,  Leo  Greenough,  Spokane,  Wash.; 

Sec’y-Treas.,  W.  J.  Beaton,  Spokane,  Wash. 

Operating  Dept.:  Asst,  Mgr.,  R.  E.  Walters,  Troy;  Mill  Supt., 
L.  E.  Warner,  Troy;  Mine  Supt.,  Jack  Grills,  Troy. 

1200  H.  P.  Electric. 

No.  men  employed:  150  to  200. 

Ores:  Silver,  lead,  zinc,  gold. 

Daily  output:  200  tons. 

Miscellaneous  Information:  1200  H.  P.  hydro-electric  power  plant; 
5 y2  miles  36-inch  gauge  railroad;  300-ton  daily  mill  capacity. 


SOUTHERN  CROSS  MINE  (A.  C.  M.  Co.).  Southern  Cross. 

Location:  Deer  Lodge  County. 

Officers:  Supt.,  J.  C.  O’Brien,  Southern  Cross. 

Electric  power. 

No.  men  employed:  85. 

Ores:  Gold  in  iron  and  lime. 

Daily  output:  90  tons. 

1918  output:  45,000  tons. 


STERLING  MINING  & MILLING  CO.  Silver  Camp. 

Location:  Heddlestone  Mining  District,  Lewis  and  Clark  County. 
Officers:  Pres.,  F.  W.  Rader,  Pullman,  Wash.;  Vice-Pres.,  W.  H. 
Rader,  Ellensburg,  Wash.;  Sec’y-Treas.,  L.  O.  Howard,  Pull- 
man, Wash. 

Operating  Dept.:  Gen.  Mgr.,  L.  O.  Howard,  Pullman,  Wash.; 

Resident  Mgr.,  Archie  McDonald,  Flesher,  Mont.;  Supt.,  U. 
J.  lones,  Flesher,  Mont. 

125  H.  P.  Steam. 

No.  men  employed:  25. 

Ores:  Silver,  lead,  zinc. 

Miscellaneous  Information:  Mine  ready  to  produce  100  tons  daily; 
mill  running  one  shift. 


ST.  PAUL-MONTANA  MINING  CO.  Maiden. 

Location:  Gilt  Edge  Mining  District,  Fergus  County. 

Officers:  Pres.,  C.  W.  Amos,  St.  Paul,  Minn.;  Sec’y-Treas.,  Wm. 
Biadin,  St.  Paul,  Minn. 

Operating  Dept.:  Mgr.,  W.  B.  Coolidge,  Maiden. 

160  H.  P.  Steam. 

No.  men  employed:  4. 

Ores:  Gold. 


—22— 


SYNDICATE  COPPER  MINING  CO.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
Officers:  Pres.,  W.  W.  McDowell,  Butte;  Sec’y,  W.  E.  Reynolds, 
Butte. 

Miscellaneous  Information:  This  company  was  a holding  com- 
pany for  the  Tuolumne  Copper  Mining  Company  and  the 
Colusa  Leonard  Mining  Company. 


TARBOX  MINING  COMPANY.  Saltese. 

Location:  Denemora  Mining  District,  Mineral  County. 

Officers:  Pres.,  Richard  Daxon,  Wallace,  Idaho;  Sec’y-Treas., 

John  T.  Rerguson,  Wallace,  Idaho. 

Operating  Dept.;  Mgr.,  Richard  Daxon,  Wallace,  Idaho. 

150  H.  P.  Steam. 

No.  men  employed:  10. 

Ores:  Lead,  silver,  zinc. 

TENDERFOOT  COPPER  MINING  CO.  Monarch. 

Location:  Cascade  County. 

Officers:  Pres.,  John  Whitted;  Vice-Pres.,  Dougold  McCallum; 
Second  Vice-Pres.,  Thomas  Ashton;  Treas.,  R.  B.  Noble; 
Sec’y,  R.  W.  Berry;  all  Great  Falls. 

Hand  Power. 

Ores:  Copper,  gold,  silver. 

Miscellaneous  Information:  Developing  ten  mining  claims,  four 
of  which  are  patented. 


TIMBER  BUTTE  MILLING  CO.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
Officers:  Mgr.,  W.  A.  Rossberg;  Efficiency  Eng.,  D.  W.  Buckby; 
Mill  Foreman,  R.  McGillivray;  Asst.  Mill  Foreman,  T.  C. 
Nilson;  Research  Eng.,  G.  E.  Sheridan;  Concentration  Eng., 
I.  O.  Proctor;  all  of  Butte,  Montana. 

2300  H.  P.  Electric. 

No.  men  employed:  200. 

Ores:  Concentrator  treats  Elm  Orlu  crude  zinc  ore,  and  retreats 
Colusa  Parrot  Copper  Mining  Company  copper  tailings. 

Daily  output:  700  tons  zinc  ore;  1,300'  tons  copper  tails. 

1918  output:  190,000  tons  crude  zinc  ore;  387,000  tons  copper  tails. 


TRIUMPH  GOLD  MINING  CO.  Princeton. 

Location:  South  Boulder  Mining  District,  Granite  County. 
Officers:  Pres,  and  Treas.,  L.  U.  Loomis,  Philipsburg;  Sec’y, 

G.  D.  Loomis,  Philipsburg. 

40  H.  P.  Steam. 

Ores:  Silver,  gold,  copper,  lead. 

No.  men  employed:  20  (building  road). 

Miscellaneous  Information:  Installing  an  air  compressor  to  sink 
main  shaft;  in  development  stage. 


TUOLUMNE  COPPER  MINING  COMPANY.  Butte. 

Location:  Summit  Valley  Mining  District,  Silver  Bow  County. 
Officers:  Pres.,  Ed.  Hickey,  Butte;  Vice-Pres.,  Wm.  P.  Jahn, 


—23— 


Milwaukee,  Wis.;  Sec’y,  J-  J Harrington,  Butte;  Treas.,  Frank 
K.  Nilson,  Butte. 

Operating  Dept.:  Gen.  Mgr.,  Paul  A.  Gow,  Butte;  Asst.  Gen. 

Mgr.,  Herbert  M.  Fay,  Butte. 

600  H.  P.  Electric. 

No.  men  employed:  100. 

Ores:  Copper  and  silver. 

Daily  output:  100  tons. 

1918  output:  25,000  tons. 

Miscellaneous  Information:  Company  owns  Tuolumne,  Main 

Range,  and  Colusa  Leonard  Extension  Mines. 


WAR  EAGLE  MINING  CO.  • Harlem. 

Location:  Little  Rockies  Mining  District,  Chouteau  County. 
Officers:  Pres.,  J.  C.  Arbogast,  Harlem;  Vice-Pres.,  Ike  Duncan, 
Chinook;  Sec’y-Treas.,  G.  M.  Everett,  Harlem. 

20  H.  P.  Gasoline. 

Miscellaneous  Information:  Development  work  only. 


WESTERN  SMELTING  & POWER  CO.  Cooke. 

Location:  New  World  Mining  District,  Park  County. 

Officers:  Pres,  and  Gen.  Mgr.,  G.  L.  Tanzer;  Sec’y.  J-  J-  Black; 

Treas.,  Geo.  B.  Baker;  all  Seattle,  Wash. 

Operating  Dept.:  Mgr.,  Wm.  M.  Tanzer;  Mine  Supt.,  F.  A.  Han- 
cock; Elec.  Eng.,  Ingvald  Gronvold;  all  Cooke,  Mont. 

1000  H.  P.  Hydro-Electric, 

No.  men  employed:  75. 

Ores:  Copper  (Chalcopyrite),  galena;  all  ores  containing  values 
in  gold  and  silver. 

Miscellaneous  Information:  Development  work  only. 

WHITLATCH  MINE.  Union  ville. 

Location:  Unionville  Mining  District,  Lewis  and  Clark  County. 
Lessee  and  Operator:  A.  R.  Shennan,  Box  351,  Helena,  Mont. 

80  H.  P.  Electric  and  Compressed  Air. 

No.  men  employed:  4. 

Ores:  Silicious  gold  and  silver. 

1918  output:  300  tons. 

Miscellaneous  Information:  Development  work  only. 

WICKES-CORBIN  COPPER  MINING  CO.  Wickes. 

Location:  Colorado  Mining  District,  Jefferson  County. 

Officers:  Pres.,  S.  A.  Balliet,  Helena;  Sec’y-Treas.,  L.  C.  Henry, 
Helena. 

Ores:  Silver,  lead,  and  copper. 

Miscellaneous  Information:  Development  work  only. 

YELLOWSTONE  MINING  CORPORATION.  Cooke. 

Location:  New  World  Mining  District,  Park  County. 

Officers:  Pres.,  W.  E.  Wolfenden,  Roanoke,  Va.;  Sec’y,  Samuel 
T.  Rhodes,  Roanoke,  Va. 

Operating  Dept.:  Mgr.,  J.  E.  Wholey,  Cooke,  Mont. 

Ores:  Lead,  silver,  gold,  and  copper. 

Miscellaneous  Information:  Shipped  five  cars  from  Stump  Mine 
last  year;  surveying  15  claims  for  patent  at  present. 


—24— 


DIRECTORY  OF  MONTANA  OPERATING  COAL 

MINES 


ANACONDA  COPPER  MINING  CO.,  Coal  Dept.  Washoe. 

Location:  Deer  Lodge  County. 

Officers:  Gen.  Mgr.  Coal  Dept.,  F.  W.  C.  Whyte,  Anaconda; 

Supt.,  Thomas  Good,  Washoe. 

500  H.  P.  Steam  and  Electric. 

No  men  employed:  200. 

Daily  output:  900  tons. 

1918  output:  147,774  tons. 


ARMINGTON  COAL  CO.  Armington. 

Location:  Cascade  County. 

Operator:  J.  O.  Rundall. 

Mule  Power. 

No.  men  employed:  2. 

Daily  output:  15  tons. 

Miscellaneous  Information:  Property  just  opened. 


BAYES  COAL  MINE.  Bayes. 

Owner:  Victor  Stoban,  Bayes. 

No.  men  employed:  2. 

Daily  output:  6. 

1918  output:  300  tons. 

BEAR  CREEK  COAL  CO.  Bearcreek. 

Location:  Carbon  County. 

Officers:  Pres.,  Peter  Yegen,  Billings;  Vice-Pres.,  J.  Harry 

Wright,  Bearcreek;  Sec’y-Treas.,  C.  P.  Hamriet,  Bearcreek. 
Operating  Dept.:  Supt.,  C.  P.  Hamriet,  Bearcreek. 

250  H.  P.  Electric. 

No.  men  employed:  185. 

Daily  output:  800  tons. 

1918  output:  135,000  tons. 


BIG  SANDY  COAL  MINE.  Big  Sandy. 

Location:  Chouteau  County. 

Proprietor:  C.  C.  Mack,  Big  Sandy. 

Foreman:  Chas.  Tivoni,  Big  Sandy. 

Hand  power. 

No.  men  employed:  3 to  8. 

Daily  output:  10  tons. 

1918  output:  2,700  tons. 


—25— 


BROWN  COAL  COMPANY.  Sand  Coulee. 

Location:  Cascade  County. 

Officers:  Pres.,  J.  W.  Freeman,  Great  Falls;  Vice-Pres.,  John  L. 

Ross,  Great  Falls;  Sec’y-Treas.,  Ernest  Downing,  Great  Falls. 
Operating  Dept.:  Mgr.,  Ernest  Downing,  Great  Falls;  Supt.,  John 
Latham,  Sand  Coulee;  Outside  Foreman,  Carl  Schmidt,  Sand 
Coulee. 

Electric  power. 

No.  men  employed:  98  to  105. 

Daily  output:  525  tons. 

1918  output:  109,295  tons. 


BRIDGER  COAL  MINING  CO.  Bridger. 

Location:  Carbon  County. 

Officers:  Gen.  Mgr.,  W.  E.  Pinkney,  Bridger;  Cashier,  J.  S.  Em-- 
mett,  Bridger. 

500  H,  P.  Electric. 

No.  men  employed:  20. 

Daily  output:  40  tons. 

1918  output:  9,088  tons. 

CARBON  COAL  & COKE  CO.  Sand  Coulee. 

Location:  Cascade  County. 

Officers:  Pres,  and  Mgr.,  Geo.  Wilson,  Sand  Coulee;  Vice-Pres. 
and  Treas.,  H.  E.  Dawson,  Sand  Coulee;  Sec’y,  Anthony 
Morton,  Sand  Coulee;  Supt.,  Wm.  Navin,  Sand  Coulee. 

350  H.  P.  Steam  and  Electric. 

No.  men  employed:  80. 

Daily  output:  400  tons. 

19t8  output:  102,248  tons. 


CHESTNUT  HILL  COAL  CO.  Storrs. 

Location:  Gallatin  County. 

Officers:  Pres.,  John  Aakjer,  Bozeman;  Treas.  and  Supt.,  William 
Maxev. 

Miscellaneous  Information:  Development  work  only. 


EAGLE  COAL  COMPANY.  Bearcreek. 

Location:  Carbon  County. 

Officers:  Pres.,  J.  T.  Flaherty,  Red  Lodge;  Vice-Pres.,  H.  A. 
Simmons,  Red  Lodge;  Sec’y.  and  Treas.,  J.  V.  Flaherty,  Red 
Lodge;  Mgr.,  J.  T.  Flaherty,  Bearcreek;  Foreman,  J.  F.  Lob- 
dell,  Bearcreek. 

60  H.  P.  Electric. 

No.  men  employed:  30. 

Daily  output:  150  tons. 

1918  output:  None. 


GASS  COAL  MINE. 

Location:  Wibaux  County. 


Yates. 


-26— 


Operator:  A.  R.  McCloskey,  Yates. 

80  H.  P.  Steam. 

1918  output:  1,200  tons. 

Miscellaneous  Information:  Closed  on  account  of  litigation. 


HELL  GATE  COAL  CO.  Missoula. 

Location:  Missoula  County. 

Officers:  Pres.,  S.  H.  Draper,  Missoula;  Vice-Pres.,  E.  S.  Hath- 
away, Missoula;  Treas.,  H.  L.  Shapard. 

60  H.  P.  Electric. 

Miscellaneous  Information:  Not  operating. 


INDEPENDENT  MINING  CO.  Roundup. 

Location:  Musselshell  County. 

Owner:  G.  J.  Jeffries,  Roundup. 

75  H.  P.  Electric. 

No.  men  employed:  30. 

Daily  output:  150  tons. 

1918  output:  50,000  tons. 


INTERNATIONAL  COAL  CO.  Bearcreek. 

Location:  Carbon  County. 

Officers:  Pres.,  W.  A.  Talmage,  Joliet;  Sec’y-Treas.,  J.  Harry 

Wright,  Bearcreek;  Gen.  Mgr.,  W.  H.  Franklin,  Bearcreek. 
300  H.  P.  Electric  and  Steam. 

No.  men  employed:  75. 

Daily  output:  300  tons. 

1918  output:  53,620  tons. 


JACKMAN  COAL  MINING  CO.  Near  Forest  Grove 

at  Jackman  Spur. 

Location:  Fergus  County. 

Officers:  Vice-Pres.,  John  B.  Ritch,  Lewistown;  Sec’y-Treas.,  E. 

W.  Mettles,  Lewistown. 

Hand  power. 

No.  men  employed:  10. 

Daily  output:  25  to  30  tons. 


MACKTON  COAL  CO.  Big  Sandy. 

Location:  Chouteau  County. 

Officers:  Pres,  and  Mgr.,  W.  R.  Hensen,  Chinook;  Sec’y-Treas., 
Hans  H.  Lehfeldt,  Big  Sandy;  Supt.,  L.  S.  Proctor,  Big  Sandy. 
500  H.  P.  Electric. 

No.  men  employed:  5 to  50. 

Daily  output:  25  tons. 

1918  output:  8,300  tons.- 


—27— 


Chinook. 


MILK  RIVER  COAL  CO. 

Location:  Blaine  County. 

Officers:  Pres.,  Jurgen  Ku'hr,  Chinook;  Vice-Pres.,  William  Duke, 
Chinook;  Treas.,  Thomas  O’Hanlon,  Chinook;  Foreman,  Clar- 
ence Sargent,  Chinook. 

No.  men  employed:  10. 

Daily  output:  35  tons. 

1918  output:  7,765  tons. 


MILLARD  COAL  COMPANY.  Belt. 

Location:  Cascade  County. 

Officers:  Mgr.,  H.  W.  Millard,  Belt. 

28  H.  P. -Electric. 

No.  men  employed:  7 
Daily  output:  40-50  tons. 

1918  output:  3,292  tons. 


MONTANA  COAL  & IRON  CO.  Washoe. 

Location:  Deer  Lodge  County. 

Officers:  Pres.,  Thos,  M.  Kearney,  Racine,  Wis.;  Vice-Pres.  and 
Mgr.,  J.  M.  Freeman,  Washoe;  Asst.  Treas.,  George  McMillan, 
Washoe. 

Operating  Dept.:  Gen.  Mgr.,  J.  M.  Freeman,  Washoe;  Supt.,  W. 

R.  Freeman,  Washoe;  Sales  Mgr.,  George  McMillan,  Washoe. 
300  H.  P.  Steam  and  Electric. 

No.  men  employed:  564. 

Daily  output:  1,500  tons. 

1918  output:  307,606  tons. 

Miscellaneous  Information:  Operating  two  mines  in  Bearcreek 

field. 


NATIONAL  COAL  MINING  CO.  Sand  Coulee. 

Location:  Cascade  County. 

Officers:  Pres,  and  Mgr.,  Jas.  R.  Brown,  Sand  Coulee 
150  H.  P.  Electric. 

No.  men  employed:  52. 

Daily  output:  210  tons. 


NELSON  COAL  COMPANY.  Sand  Coulee. 

Location:  Cascade  County. 

Officers:  Pres,  and  Treas.,  J.  W.  McClure,  Great  Falls;  Vice- 
Pres.,  Geo.  E.  McClure,  Great  Falls;  Scc’y,  M.  W.  Hanks, 
Stillwater,  Minn. 

Operating  Dept.:  Mgr.,  J.  W.  McClure,  Great  Falls;  Foreman, 
Geo.  Cooley,  Sand  Coulee;  Mine  Mgr.,  Harry  Thomas,  Sand 
Coulee. 

200  H.  P.  Electric. 

No.  men  employed:  100. 

Daily  output:  500  tons. 

1918  output:  161,348  tons. 


—28— 


Sand  Coulee. 


PEARCE  COAL  COMPANY. 

Location:  Cascade  County. 

Officers:  Pres.,  Dan  Tracy,  Great  Falls;  Vice-Pres.,  H.  P.  Brown, 
Great  Falls;  Sec’y-Treas.,  Wm.  Thornton,  Great  Falls;  Supt., 
Robert  Lindsay,  Sand  Coulee. 

45  H.  P.  Electric. 

No.  men  employed:  22. 

Daily  output:  94  tons. 

1918  output:  37,332  tons. 


PEERLESS  COAL  MINE.  Plentywood. 

Location:  Sheridan  County. 

Operators  and  Owners:  Pierce  & Wheeler,  Plentywood. 

12  H.  P.  Electric. 

No.  men  employed:  3. 

Daily  output:  20  tons. 

1918  output:  6,838  tons. 


PINE  CREEK  COAL  COMPANY.  Pray. 

Location:  Park  County. 

Officers:  Gen.  Mgr.,  George  H.  Bottamy,  Livingston;  Mine  Supt., 
Harry  Bottamy,  Pray;  Sales  Agt.,  George  H.  Brown,  Wilsall. 
Operating  Dept.:  Operator  and  P.  A.,  George  H.  Bottamy,  Liv- 
ingston; Sec’y-Treas.,  G.  Henry  Bottamy,  Livingston. 

100  H.  P.  Steam,  and  Mule. 

No.  men  employed:  10. 

Daily  output:  10  to  20  tons. 

1918  output:  1,200  tons. 


PUTNAM  COAL  CO.  Culbertson. 

Owner:  Mrs.  E.  Putnam,  Culbertson. 

Hand  Power. 

No.  men  employed:  3. 


REPUBLIC  COAL  CO.  Roudup. 

Location:  Musselshell  County. 

Officers:  Pres.,  E.  D.  Sewall,  Chicago,  111.;  . Vice-Pres.,  James 
Needham,  Chicago,  111.;  Chief  Eng.,  C.  F.  Brenn,  Chicago,  111. 
Operating  Dept.:  Supt.,  Wm.  Redshaw,  Roundup;  Master  Me- 
chanic, Albert  Gately,  Roundup. 

1250  H.  P.  Steam  and  Electric. 

No.  men  employed:  525. 

Daily  output:  3,000  tons. 

1918  output:  663,267  tons. 


ROUNDUP  COAL  MINING  CO.  Roundup. 

Location:  Musselshell  County. 

Officers:  Pres.,  G.  W.  Megeath,  Omaha,  Neb.;  Vice-Pres.,  W.  F. 
Megeath,  Omaha,  Neb.;  Treas.,  G.  A.  Rehm,  Omaha,  Neb. 


—29— 


Operating  Dept.:  Gen.  Mgr.,  H.  S.  Hopka,  Roundup;  Chief  Eng., 
L.  J.  Cake,  Roundup;  Supt.,  John  Sanderson,  Carpenter  Creek. 
800  H.  P.  Electric. 

No.  men  employed:  600. 

Daily  output:  3,600  tons. 

1918  output:  530,000  tons. 


SMOKELESS  AND  SOOTLESS  COAL  CO.  Washoe. 

Location:  Deer  Lodge  County. 

Officers:  Pres.,  J.  F.  Brophy,  Red  Lodge;  Vice-Pres.,  J.  S. 

Brophy,  Frostburg,  Md.;  Sec’y,  K.  C.  Brophy,  Red  Lodge; 
Gen.  Mgr.,  J.  F.  Brophy,  Red  Lodge. 

Electric  Power. 

No.  men  employed:  85. 

Daily  output:  200  tons. 

1918  output:  48,385  tons. 


STULLER  & TRIPLETT.  Froid. 

Location:  Sheridan  County. 

Owners:  J.  C.  Stuller  and  Ira  Triplett. 

Horse  Power. 

No.  men  employed:  4. 

Daily  output:  12  tons. 

1918  output:  2,500  tons. 


THOMSEN  MINE.  Plentywood. 

Location:  Sheridan  County. 

Owner:  Hans  Thomsen,  Plentywood. 

Horse  Power. 

No.  men  employed:  3. 

Daily  output:  18  tons. 


WEST  BUTTE  COAL  CO. 

Location:  Toole  County. 

Owner:  P.  J.  McDermott,  Westbutte. 
No.  men  employed:  4. 

Daily  output:  6 tons. 

1918  output:  981  tons. 


Westbutte. 


—30— 


Pic;.  1. — THE  WASHOE  SAMPLER  OP  THE  ANACONDA  MINING  COMPANY,  AT  BUTTE,  MONTANA. 


UNIVERSITY  OF  MONTANA  BULLETIN 

BUREAU  OF  MINES  AND  METALLURGY  SERIES  NO.  3 


MECHANICAL  ORE  SAMPLING  IN 
MONTANA 


By  H.  B.  PULSIFER 


\ H t li oK&KT  Of  ' 

FE3  % 6 1925 

UNIVERSITY  OF  ILLINOIS 

STATE  SCHOOL  OF  MINES 
BUTTE,  MONTANA 


March,  1920 


4 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


STATE  BUREAU  OF  MINES  AND  METAL- 
LURGY STAFF 


CLAPP,  CHARLES  H.  - - - - - Director  and  Geology 

PhD.,  Massachusetts  Institute  of  Technology,  1910. 

ADAMI,  ARTHUR  E.  -------  - Mining  Engineer 

E.  M.,  Montana  State  School  of  Mines,  1907. 

PUESIFER,  H.  B.  -------  Metallurgy  and  Safety 

B.  S.,  Massachusetts  Institute  of  Technology,  1903; 


Ch.  E.,  Armour  Institute  of  Technology,  1915; 
M.  S.,  University  of  Chicago,  1918. 


V/3  (SUM^ 


A4  9^3 
'Tvc  • 3 

CONTENTS 

Page 

Introduction  7 

Authorization 7 

Object : ; 7 

Acknowledgments 7 

Purpose  of  sampling .. 8 

Principles  of  sampling 9 

Necessary  operations 10 

Crushing  and  grinding 11 

Dividing  or  selecting 12 

Mixing  the  sample 12 

Drying  the  sample l..~ 17 

Cone  and  quarter  sampling 17 

Probability  sampling 19 

The  largest  pieces 21 

High  value  minerals 23 

Equipment  for  sampling 24 

Crushing  and  grinding  machines 24 

Dividing  instruments - 26 

The  hand  shovel 26 

The  split  shovel : 26 

Riffle  cutters 26 

Pipe  samplers 29 

The  Brunton  vibratory  sampler 31 

The  Brunton  oscillatory  sampler 34 

The  East  Butte  sampler ’ 34 

The  Vezin  sampler 34 

The  Snyder  sampler 36 

Mixing  machines 38 

Drying  machines 40 

Sampling  of  test  lot  by  State  Bureau 40 

Mill  flow  sheets.. 42 

Sampling  mills  in  Montana 46 

The  Washoe  Sampler 46 

East  Helena  sampling  mills r 49 

The  East  Butte  sampling  mill 57 

Anaconda  sampling  mills 60 

Sampling  in  Montana  concentrating  and  cyaniding  mills 67 

Summary  and  conclusions 68 

Important  publications  on  sampling 69 

Index 71 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


ILLUSTRATIONS 

Page 

Figure  1.  The  Washoe  Sampler Frontispiece 

2.  Stand  riffle  cutter .-. 14 

3.  Cone  and  quarter  sampling — spreading 16 

4.  Cone  and  quarter  sampling — mixing 18 

5.  Probability  curve  for  sampling  results 20 

6.  Split  shovel  sampling 25 

7.  Inclined  table  riffle 27 

8.  Corner  of  East  Helena  bucking  room 28 

9.  Pipe  sampling  of  flotation  concentrates 30 

10.  Blades  of  Brunton  vibratory  sampler 32 

11.  Mechanism  of  Brunton  oscillatory  sampler 32 

12.  First  sampler  and  first  rolls  at  Washoe  Sampler 33 

13.  East  Butte  type  of  sampler _ :.... 35 

u 14.  Vezin  sampler . ........  36 

15.  Snyder  sampler 37 

16.  Drum  mixer,  sampler,  and  rolls  in  East  Butte  mill 39 

17.  Taylor  and  Brunton  sampling  system 47 

18.  View  of  Washoe  Sampler  from  the  east 48 

19.  Third  cutter  and  third  rolls  in  Washoe  Sampler 50 

“ 20.  Unloading  ore  at  East  Helena  No.  1 mill 52 

“ 21.  Sampling  mill  No.  1 at  East  Helena 53 

“ 22.  First  floor  equipment  at  East  Helena  No.  1 mill 54 

“ 23.  Vezin  sampler  wings  at  East  Helena  sampling  mills 55 

“ 24.  Steel  sampling  floor  at  East  Helena 56 

“ 25.  East  Butte  sampling  mill... 58 

“ 26.  Third  sampler  and  third  rolls  in  East  Butte  mill 59 

“ 27.  Anaconda  sampling  mill 61 

“ 28.  Diagram  of  Anaconda  sampling  mill 62 

“ 29.  First  sampler  and  second  crusher  in  Anaconda  mill 63 

“ 30.  Bucking  room  at  Anaconda  sampling  mill 65 


OBJKCT 


7 


INTRODUCTION 

AUTHORIZATION 

The  bill  creating  the  Montana  State  Bureau  of  Mines  and  Metal- 
lurgy, enacted  by  the  Legislative  Assembly  of  Montana  for  1919 
(Chapter  161,  Page  311),  states  that  it  is  one  of  the  objects  and 
duties  of  the  new  bureau,  “To  study  the  mining,  milling,  and  smelting 
operations  carried  on  in  the  State,  with  special  reference  to  their 
improvement”,  also,  “To  prepare  and  to  publish  bulletins  and  reports, 
with  necessary  illustrations  and  maps,  which  shall  embrace  both  a 
general  and  detailed  description  of  the  natural  resources  and  geology, 
mines,  mills, ^ and  reduction  plants  of  the  State.” 

OBJECT 

A study  of  sampling  and  the  sampling  facilities  of  Montana  is 
presented,  in  accordance  with  the  above  authorization,  to  widen  and 
deepen  the  general  knowledge  relating  to  the  common  and  necessary, 
yet  rather  technical  work  of  sampling.  It  is  hoped  that  prospectors 
and  miners  will  benefit  from  the  study,  for  their  interests  have  been 
kept  prominently  in  view.  The  sampling  mills  in  which  ore  sellers 
will  find  personal  interest  have  been  thoroughly  studied  and  their 
reliability  tested  by  an  expensive  series  of  samplings  to  demonstrate 
their  precision  on  an  ordinary  lot  of  ore.  It  is  felt  that  even  small 
advances  toward  the  uniformity,  precision,  and  efficiency  of  sampling 
mean  so  much  to  the  industry  as  to  warrant  even  far  more  effort  and 
cost  than  is  represented  in  this  study. 

ACKNOWLEDGMENTS 

The  managements  of  the  American  Smelting  and  Refining  Com- 
pany, the  Anaconda  Copper  Mining  Company,  and  the  East  Butte 
Copper  Mining  Company  have  heartily  welcomed  the  study  and  have 
assisted  in  every  way  possible.  Each  company  has  put  itself  to  expense 
and  trouble  to  join  in  the  work. 

Particular  acknowledgments  are  due  Messrs.  Smith,  Morse,  and 
Adams  of  the  American  Smelting  and  Refining  Company,  to  Messrs. 
Laist,  Bender,  Gillie,  Margetts,  and  Demond  of  the  Anaconda  Copper 
Mining  Company,  and  to  Messrs.  Rohn  and  Beaudin  of  the  East  Butte 
Copper  Mining  Company.  The  men  mentioned  have  been  personally 
helpful  in  forwarding  and  correcting  the  work. 

Dr.  Clapp  of  the  State  Bureau  has  taken  a strong  interest  in  the 
work  and  helpfully  directed  the  preparation  of  the  report. 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


THE  PURPOSE  OF  SAMPLING 

The  sampling  of  a lot  of  ore  is  carried  out  in  order  to  supply  the 
analyst  with  a 4-ounce  envelope  of  finely  ground  powder  which,  when 
selections  are  made  in  from  half-gram  to  thirty-gram  portions,  shall 
give  the  analyst  average  results  with  a precision  of  about  one  part  in 
fifty  for  the  important  components,  or  elements,  moisture  excepted. 
The  usual  chemical  determinations  are  for  gold,  silver,  copper,  lead, 
zinc,  sulphur,  iron,  silica,  lime,  and  magnesia,  and  for  special  elements 
in  particular  ores. 

Sampling  is  thus  seen  to  have  an  amazing  purpose  in  view;  to  take 
from  a lot  of  ore — be  it  one  ton,  fifty  tons,  or  five  hundred  tons — 
only  about  thirty-two  ounces  of  material  which  shall  uniformly  con- 
tain all  the  components  of  the  original  lot  in  exactly  the  proportions 
in  which  they  exist  in  the  original  lot  of  ore.  Even  this  final  sample 
of  about  thirty-two  ounces  must  be  capable  of  division  so  that  the 
different  packets  into  which  it  is  separated  must  be  chemical  duplicates 
of  each  other  and  supply  seller,  buyer,  control  analyst,  smelter,  and 
umpire  analyst  with  as  nearly  identical  results  as  possible.  Yet,  in 
spite  of  the  enormous  difficulties  in  practice,  perfectly  satisfactory 
sampling  is  actually  attained  daily. 

The  lot  of  ore  to  be  worked  upon  will  likely  contain  very  fine 
material,  sandy  material,  and  sizes  up  to  big  chunks;  it  will  contain 
desirable  minerals  and  undesirable  rocky  gangue;  it  may  contain  free 
metals,  clayey  gouge,  and  crystals  in  all  degrees  of  purity.  It  is  remark- 
able that  the  task  can  be  done  at  all;  it  is  nothing  less  than  one  of  the 
great  achievements  of  modern  engineering  and  industry  that  it  can  be 
done  easily,  quickly,  cheaply,  and  with  precision. 

Ordinary  sampling  mills  will  secure  a 100-pound  sample  from  a 
50-ton  lot  of  ore  in  from  fifteen  minutes  to  two  hours,  and  then  from 
this  sample  the  sample  man  in  the  bucking  room  will  produce  the 
analyst’s  packets  of  thoroughly  ground,  dried,  and  mixed  pulp  in 
another  hour. 

The  cost  of  sampling  varies  from  5 cents  to  $1.50  a ton,  depending 
upon  the  amount,  character  of  ore,  and  the  method  and  equipment 
used. 

Sampling  has  accomplished  its  purpose  if  the  small  packet  will 
supply  the  half-gram,  fifteen-gram,  or  thirty-gram  selections  for  the 
analyst  so  that  he  can  get  his  results  with  the  required  precision.  The 
sampling  is  satisfactory  if  the  average  results  on  different  selections 
from  the  same  packet,  or  on  selections  from  different  packets,  or  on 
selections  from  different  samplings,  agree  to  one  part  in  fifty  parts, 
or,  as  they  sometimes  do,  to  one  part  in  one  hundred  parts.  The  pre- 
cision may  be  less  with  elements  present  in  excessively  small  amounts, 
like  gold  and  silver.  The  chemical  work  is  subject  to  both  constant 
and  chance  errors,  so  that  single  results,  or  too  many  significant 
figures  in  the  results,  have  little  meaning;  error  may  come  as  likely 
from  the  analytical  work  as  from  the  sampling  operation. 


PRINCIPLES  OF  SAMPLING 


Sampling  has  failed  of  its  purpose  if  selections  from  packets  do 
not  agree  within  the  desired  limits,  or  if  the  different  packets  from 
the  same  sampling  do  not  agree,  or  if  packets  from  different  samplings 
are  discordant.  The  best  test  of  accuracy  in  sampling  is  to  resample 
or  sample  by  another  method.  It  is  rarely  cheap  of  practicable  to 
actually  extract  the  desired  metal  or  attempt  to  separate  a compound 
from  an  entire  large  lot  in  order  to  determine  its  amount;  in  such  a 
case  the  recovery  figure,  instead  of  the  composition  figure,  is  obtained, 
because  the  losses  which  the  chemist  compensates  for,  the  plant 
operator  cannot  avoid. 

Whoever  mines  ore,  sells  it  on  the  results  of  the  analysis  of  a 
sample;  ore  is  purchased  on  its  value  as  determined  by  sampling;  the 
plants  are  operated  on  a basis  of  results  from  sampled  materials; 
efficiencies  and  losses  are  all  based  on  results  from  samplings. 
Sampling  is  therefore  one  of  the  most  vital  and  necessary  operations 
of  modern  mining  and  metallurgical  industry. 


PRINCIPLES  OF  SAMPLING 

*Woodbridge  in  a recent  paper  published  by  the  United  States 
Bureau  of  Mines  defines  sampling  as  follows:  “The  correct  sampling 
of  a lot  of  ore  is  the  process  of  obtaining  from  it  a smaller  quantity 
that  contains,  in  unchanged  percentages,  all  the  constituents  of  the 
original  lot.”  He  further  qualifies  and  defines  the  operations  in  his 
next  paragraph:  “The  commercial  object  of  sampling  is  accomplished 
when  the  ultimate  sample  obtained  meets  the  above  conditions  within 
an  allowable  limit  of  error,  and  has  been  obtained  with  reasonable 
speed  and  at  a moderate  cost.  The  final  sample  should  be  dry  and  of 
such  bulk  and  degree  of  fineness  as  to  be  immediately  available  for 
the  determination  by  the  assayer  or  chemist  of  one  or  more  of  its 
constituents.” 


THE  OPERATIONS  OF  SAMPLING 

Four  wholly  different,  yet  essential,  sorts  of  work  may  be  done  to 
accomplish  the  intended  purpose  of  sampling.  The  four  operations  are: 

1.  Crushing,  or  grinding. 

2.  Selecting — dividing  or  cutting. 

3.  Mixing. 

4.  Drying. 

These  essential  operations  are  carried  through  to  varying  degrees 
and  in  whatever  order  the  conditions  require.  Thus,  with  flotation 


WVoodbridge,  J.  T.;  U.  S.  Bureau  of  Mines,  Technical  Paper  86  (1916). 


10 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


concentrates,  which  are  already  finely  ground  and  well  mixed  in  pro- 
duction, the  work  is  largely  in  cutting  out  numerous  selections,  drying, 
regrinding  the  lumps  made  by  the  drying,  mixing  the  pulp,  and 
dividing  it  between  the  several  packets.  A lot  of  coarse,  rocky  ore 
may  be  dry  and  excessively  hard;  in  this  case  the  work  is  mostly 
crushing  and  selecting  until  the  small  final  portion  is  dried,  finely 
ground,  mixed,  and  split  for  the  assayers’  packets. 

Successful  sampling  demands  that  a rational  sequence  be  followed 
and  that  attention  be  continually  give  to  certain  fundamental  con- 
ditions, explained  later,  lest  some  slip  or  unexpected  influence  vitiate 
the  entire  work.  It  is  self-evident  that  the  final  result  cannot  be  more 
perfect  than  the  most  imperfect  step  in  the  sequence;  if  six  divisions 
are  made,  and  one  is  imperfectly  done,  perfect  work  in  the  other  five 
does  not  compensate. 

Sampling  can  frequently  be  accomplished  by  different  methods  or 
by  changing  the  sequence  of  the  steps;  one  usually  uses  the  method 
most  feasible  or  least  costly.  Thus,  if  one  had  a 50-ton  lot  of  lump 
ore  to  sample,  an  imaginary  way  to  get  the  required  results  might  be 
to  dry  the  entire  lot,  then  grind  it  to  pass  100  mesh,  then  mix  it 
thoroughly,  then  at  last  take  out  just  enough  of  the  dried,  ground, 
and  mixed  ore  to  fill  the  sample  packets.  For  most  metallurgical 
purposes  the  cost  of  such  an  operation  would  be  absolutely  prohib- 
itive; the  nearest  commercial  approach  to  it  is  probably  the  sampling 
of  the  Cobalt  native  silver  ores.  The  usual  western  practice  with  lump 
ores  is  to  crush  to  2-  or  3-inch  size,  select  a fifth  and  crush  it  finer, 
select  a fifth  and  crush  it  again;  and  this  sequence  is  repeated,  two, 
three,  four,  or  more,  times,  until  a small  amount  is  obtained  which 
alone  is  dried,  finely  ground,  mixed,  and  distributed  between  the 
packets. 

The  method  of  making  the  entire  lot  uniform  and  then  selecting 
a few  duplicate  portions  for  the  analyst  is  attractive  for  the  ease  and 
simplicity  of  the  few  selections  involved.  In  addition,  this  method  is 
one  which  may  come  into  use  more  and  more  on  account  of  the  lines 
along  which  metallurgy  and  industrial  chemistry  are  advancing.  Pipe 
sampling  of  concentrates  is  almost  an  example  of  this  simple  method. 
In  fact,  this  method  is  actually  followed  in  the  most  approved  manner 
of  sampling  lead  bullion.  A kettle  of  molten  lead  ready  for  casting 
into  bars  is  stirred  for  15  minutes;  as  the  stirring  continues  the 
sampler  inserts  a steel  rod,  with  a row  of  conical  depressions  in  it. 
On  the  withdrawal  of  the  rod  each  little  cone  of  lead,  which  fills  a 
depression,  will  come  out  of  the  kettle  of  the  proper  weight  for  the 
assayer  and  will  contain  the  correct  proportions  of  all  components 
of  the  kettle  of  molten  lead.  Two  lots  of  7 little  cones,  all  from  the 
same  kettle,  were  cupelled,  and  the  following  results  were  obtained: 


CRUSHING  AND  GRINDING 


11 


Series  No.  1 


Series  No.  2 


Gold  Silver 

.30  oz.  81.7  ozs. 


Gold  Silver 

.30  oz.  82.1  ozs. 


Average:  .30  82.0 


.30  82.0 

.30  81.4 

.30  82.3 

.32  82.1 

.30  82.0 

.30  82.3 


.30  82.4 

.30  82.0 

.30  81.7 

.30  82.0 

.30  82.0 

.32  81.8 

.30  82.0 


This  method  of  sampling  lead  bullion  has  given  eminently  satis- 
factory results  at  a trivial  cost.  Pipe  sampling  of  a pile,  or  carload 
of  concentrates,  is  also  a matter  of  very  slight  cost  and  will  necessarily 
give  correct  results  if  the  lot  is  uniform.  Sampling  by  taking  a few- 
small  portions  from  a uniform  lot  of  fine  material,  either  during  its 
production  or  after  it  is  in  a batch,  is  a method  which  should  always 
be  borne  in  mind;  and  if  the  proper  condition  for  this  is  to  araise 
during  the  treatment  of  any  material,  sampling  can  be  profitably 
delayed  until  that  stage  is  reached.  Unfortunately,  the  producer  of 
ore  seldom  has  his  material  in  a fine  and  uniform  condition  suitable 
for  such  sampling. 

Crushing  and  Grinding. — The  crushing  of  ore  for  sampling  pur- 
poses is  largely  a matter  of  mechanics,  power,  and  capital  outlay.  It 
usually  does  no  harm  if  some  of  the  material  is  finely  divided  during 
the  course  of  crushing  the  larger  pieces  to  the  necessary  dimensions. 
Since  a great  variety  of  sizes  will  inevitably  be  produced,  the  making 
of  fines  increases  the  number  of  particles  and  favors  the  sampling 
when  it  is  done  on  the  probability  basis. 

Many  of  the  crushing  machines  on  the  market  are  excellent  for 
reducing  ore  sizes  and  fulfil  most  of  the  expected  functions.  Capital 
outlay  is  always  a serious  consideration  and  machines  are  primarily 
installed  on  their  gross  capacities  and  not  on  the  basis  of  how  thor- 
oughly they  will  accomplish  the  crushing  task.  Sampling  mills  do 
have  a strong  claim  for  heavy  and  powerful  machinery,  since  an 
unusually  large  or  tough  piece  of  rock  slipping  through  one  machine 
may  spoil  the  sampling  because  of  its  excessive  mass  and  one-sided 
composition.  In  ordinary  ore-dressing  practice  it  means  little  if  slabs 
fall  through  machines  or  if  large  rocks  spring  the  rolls  and  fail  to  be 
well  crushed.  Ultimately  the  pieces  will  be  caught  and  crushed  or 
returned  to  the  first  crushers  by  the  sizing  devices.  But  most  sampling 
mills  do  not  have  sizing  devices  and  it  is  possible  for  large  pieces  to 
get  into  the  sample.  It  is  not  uncommon  to  find  a sample  which, 
although  90  to  99  per  cent,  is  properly  sized,  contains  a few  unduly 
large  pieces,  thus  tending  to  vitiate  the  results. 

Several  methods  may  be  proposed  for  overcoming  the  sizing  dif- 
ficulty. The  idea  of  using  very  heavy  rolls  is  neither  new  nor  impres- 


12 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGA’ 


sive.  Dodge  type  crushers,  which  make  a finer  product  than  the  Blake 
type,  would  be  only  a partial  remedy.  There  appears  to  be  a field  for 
a type  of  crushing  machine  which  shall  be  so  constructed  as  to  make 
the  passing  of  thin  slabs  impossible;  capacity  could  be  somewhat 
sacrificed  for  the  sake  of  the  sizing  feature. 

In  regard  to  grinding  the  finest  sizes  for  the  final  pulp  there 
appears  to  be  an  open  field  for  studying  the  correlation  of  grinding 
substance  with  the  work  accomplished.  A complete  study  of  this 
detail  of  sampling  and  grinding  should  include  the  composition, 
structure,  and  physical  properties  of  the  grinding  substance.  One 
important  factor  would  be  to  accurately  determine  how  much  of  the 
grinding  substance  is  abraded  to  contaminate  the  sample. 

Dividing  or  Selecting. — The  phrase,  “selecting  the  sample,”  could 
well  be  replaced  with  the  words,  “dividing  the  lot,”  for  the  idea 
inherent  in  SELECT  is  that  a division  is  made  which  is  based  on  some 
property  or  quality  of  the  portions  available.  The  word  select  is 
always  used  in  this  paper  with  the  simple  meaning  of  divide.  The 
most  vital  principle  in  any  and  all  sampling  is  that  division  shall  not 
be  dependent  on  any  quality  of  the  parts.  Whether  one  is  removing  a 
small  portion  of  a perfectly  mixed  lot,  or  whether  one  is  making  a 
thousand  mechanical  divisions,  the  separation  demands  the  absence 
of  discrimination. 

Mechanical  sampling  attains  its  best  precision  with  well-designed 
equipment  which  allows  no  division  based  on  a property  of  parts,  as 
on  the  coloring,  the  sizes,  or  the  relative  densities  of  the  ore  pieces. 
If  a piece  of  machinery  is  to  handle  pieces  of  rock  several  inches 
across  just  as  impartially  as  it  handles  quarter-inch  sizes  it  probably 
means  surprisingly  large  equipment.  When  confronted  with  the  prob- 
lem of  sampling  very  large  pieces,  the  engineer  sometimes  decides 
to  crush  enough  to  accommodate  the  sampling  machinery;  he  rarely 
builds  ungainly  machinery,  but  he  frequently  handles  large  sizes  with 
too  small  machinery.  To  the  mechanical  engineer  a compromise  is  a 
“practical”  solution  of  the  problem,  but  to  the  mining  engineer  a 
compromise  involving  even  slight  deviations  from  impartial  sampling 
is  a perversion  of  the  whole  function. 

The  precision  of  modern  mechanical  sampling,  as  based  on  the  law 
of  probability  brought  into  play  by  hundreds  and  thousands  of  divi- 
sions, is  a source  of  much  pride  and  satisfaction  to  the  engineers  and 
men  interested.  The  demonstrations  to  be  presented  in  later  para- 
graphs will  substantiate  this  opinion  and  establish  a confidence  in  the 
practice.  Mechanical  cutters  in  the  mills,  and  riffle  dividers  in  the 
bucking  rooms,  allow  ores  to  be  sampled  without  possibility  of  being 
influenced  either  by  human  craft  or  stupidity.  Also,  fortunately,  both 
speed  and  cheapness  are  in  favor  of  wholly  mechanical  sampling. 

Mixing  the  Sample. — The  mixing  of  a large  lot  of  ore  consisting  of 
large  and  small  pieces  is  almost  impossible  and,  besides,  is  wholly 


MIXING  THE  SAMPLE 


1 


useless.  When  you  try  to  do  this  you  find  that  any  method  of  hand- 
ling assorted  sizes  allows  segregation  if  the  material  is  dropped,  or 
let  roll,  or  even  moved  by  ordinary  implements.  The  material  cannot 
be  properly  sampled  by  small  selections  of  single  pieces,  because  the 
larger  pieces  exceed  the  proportionate  composition  in  all  components. 

The  mixing  of  large  lots  of  fine  ore  or  mill  products  is  not  as 
difficult  an  operation  as  the  preceding,  but  is  seldom  practicable 
unless  done  incidentally  to  the  production  or  transfer  of  the  material. 
Even  if  a lot  of  fine  ore  appears  to  he  uniformly  mixed  there  is  no 
easy  demonstration  of  the  fact,  and  it  is  much  safer  to  depend  on  a 
considerable  number  of  cuttings.  The  frequent  division  of  a fairly 
uniform  material  is  carried  out  in  practice  when  mill  streams  are 
sampled,  either  mechanically  or  by  hand,  when  cars  and  bins  of  con- 
centrates are  pipe  sampled,  and  in  shovel  sampling  by  the  tenth-  or 
fifth-shovel  method.  The  three  instances  last  mentioned  are  really 
applications  of  probability  sampling,  but  probability  sampling  used 
where  the  material  is  known  to  be  nearly  uniform,  and  where  from 
50  to  500  selections  suffice  to  establish  the  required  precision  in  the 
sample. 

A thorough  mixing  of  the  final  portion  of  pulp  previous  to  its 
division  between  the  several  packets  is  indispensable.  A large  number 
of  rollings  on  a suitable  cloth  or  paper  is  the  almost  universal  way 
to  do  the  final  pulp  mixing.  Rolling,  when  skilfully  done,  accom- 
plishes the  purpose,  but  the  great  objection  to  rolling  is  that  it  is 
tedious  and  requires  both  time  and  patience.  If  a cloth  fabric  is  used 
it  may  well  have  a pebble-grained  surface;  a paper  should  have  a 
matte  surface.  The  surfaces  of  either  fabric  or  paper  are  commonly 
colored  black  to  show  the  sample  more  easily. 

Substitutes  for  rolling  the  pulp  on  cloth  or  paper  have  been  pro- 
posed; the  Anaconda  sample  mills  use  cube  mixers  and  at  the  School 
of  Mines  a small  table  riffle  answers  the  purpose.  At  Anaconda 
both  mills  are  equipped  with  8-inch  cube  mixers  which  rotate  by 
power  and  slowly  enough  for  the  contents  to  undergo  practically 
the  same  sort  of  tumbling  which  a pulp  would  get  when  rolled  on  a 
fabric.  Cube  mixers  have  not  proved  satisfactory  in  all  cases  and 
their  use  in  the  State  is  limited  to  the  Anaconda  mills.  Classes  in 
assaying  at  the  School  of  Mines  have  recently  mixed  their  final  pulps 
by  pouring  them,  with  shakings  to  and  fro,  at  least  ten  times  through 
a table  riffle.  As  far  as  can  be  determined  in  the  the  course  of  the 
regular  assaying  work,  the  riffle  mixing  is  fully  adequate  and  will 
be  explained  in  considerable  detail. 

A riffle  cutter  may  be  used  to  make  either  a very  few  or  a greater, 
and  almost  unlimited,  number  of  cuts  during  the  division  of  an  ore 
sample.  Figure  2 shows  an  operator  pouring  a sample  through  a 
riffle  cutter  which  has  26  slots.  When  the  sample  container  rests 
on  the  edge  of  the  cutter,  and  the  material  is  merely  allowed  to  flow 
through  the  12  slots  which  extend  the  width  of  the  ore  stream, 


14 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


FIG.  2. — STAND  RIFFLE  CUTTER  USED  AT  THE  STATE  SCHOOL 

OF  MINES. 

The  cutter  lias  26,  5/a-inch  slots,  ami  is  intended  for  dividing  8-mesh 

stock. 


MIXING  THE  SAMPLE 


15 


there  will  be  6 streams  of  ore  flowing  into  the  sample  half,  and  the 
lot  may  be  said  to  be  cut  6 times  for  sample.  When  the  operator 
moves  the  container  across  the  top  of  the  riffle,  say  20  times  during 
the  .pouring,  all  of  the  slots  are  brought  into  play  and  the  lot  may  be 
cut  20x13,  or  260,  times  for  sample.  The  operator  might,  however,  take 
the  ore  from  the  container  in  a scoop  and  then  pour  it  through  in 
small  portions,  shaking  each  scoopful  20  times  across  the  riffle.  If  the 
operator  takes  a lot  of  ore  in  10  scoopfuls,  and  pours  each  across  the 
26  slots,  with  20  to  and  fro  motions,  he  makes,  altogether,  10x13x20, 
or  2,600  cuts,  for  the  sample. 

It  is  thus  seen  that  a lot  of  ore  is  very  easily  cut  into  a larger 
number  of  portions  by  merely  shaking  the  ore  stream  across  the 
riffle.  When  the  two  halves  of  the  divided  sample  have  been  united 
the  lot  of  ore  has  been  thoroughly  mixed.  Both  gross  and  minute 
inequalilies  are  dispersed  throughout  the  sample  by  cutting  and 
uniting  several  times,  in  other  words,  the  lot  has  become  unusually 
“well  mixed.” 

The  author  is  of  the  opinion,  that,  if  a lot  of  sample  pulp  is  shaken 
10  times  across  a riffle,  which  makes  1,000  cuts  for  sample  each  time, 
the  united  pulp  will  be  as  well  mixed  as  by  rolling  1,000  times  on  a 
cloth.  The  riffle  mixing  can  be  done  in  less  than  5 minutes,  while  the 
rolling  will  rarely  require  less  than  15  minutes. 

In  order  to  make  an  exacting  test  of  the  mixing  that  can  be  done 
with  a riffle  the  author  prepared  500  grams  of  quartz  and  500  grams 
of  iron  ore  by  grinding  each  and  passing  them  through  a 100-mesh 
sieve.  Each  lot  was,  of  course,  dry  and  thoroughly  mixed.  The  iron 
ore  was  poured  over  the  quartz  in  a pan  and  then  the  material  was 
poured  through  a 12-slot  riffle  giving  nearly  100  shakes  during  the 
30  seconds  required  for  the  powder  to  flow  from  the  pan.  Two  grab 
samples  of  about  half-gram  size  were  taken  on  a spatula  from  each 
half.  The  two  portions  were  united  and  the  operation  repeated.  This 
was  done  7 times  and  each  time  two  grab  samples  from  each  half 
were  taken  for  analysis.  The  chemical  results  were  as  follows: 

Quartz,  3.17%  iron;  iron  ore,  43.78%  iron;  average,  23.48%  iron. 

PERCENTAGE  OF  IRON  IN  GRAB  SAMPLES 


Ave.  Deviation 

Mixing  The  Four'  Samples  Average  from  23.48 

1st  15.72  32.72  6.04  30.80  21.32  10.44 

2nd  20.24  20.12  19.24  21.12  20.18  3.30 

3rd  -.20.12  21.40  *23.40  22.88  21.95  1.51 

4th  23.28  23.50  23.40  23.20  23.34  .15 

3th  —23.64  23.64  23.44  23.64  23.61  .13 

6th  23.56  23.64  23.44  23.64  23.57  .11 

7th  23.36  23.44  23.52  23.64  23.49  .09 


The  chemical  analyses  show  that  the  first  mixing  had  intermixed 
the  iron  ore  and  quartz  to  a very  considerable  extent,  although  far 


16 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


PIG.  3. — CONK  AND  QUARTER  SAMPLING. 

The  cone  has  been  formed  over  a wooden  cross  and  the  men  are  just  beginning  to  spread  the  pile. 


DRYING  THE  SAMPLE 


17 


from  enough  to  be  utilized.  The  second  mixing  adjusted  the  compo- 
sition to  within  a few  per  cent,  of  what  it  should  be.  The  third  mixing 
brought  practically  perfect  final  composition  in  streaks,  while  the 
fourth  mixing  doubtless  rendered  the  entire  batch  homogeneous  to 
within  1 part  in  100  parts,  which  is  of  the  order  of  the  chemical 
analyses,  themselves.  The  5th,  6th,  and  7th  mixings  changed  the  com- 
position in  an  almost  inappreciable  degree.  The  chemical  determin- 
ation of  iron  was  chosen  because  it  could  be  done  more  easily  and 
with  greater  precision  than  almost  any  other  determination  or  assay. 

Material  which  yields  identical  composition  on  haphazard  samples 
fulfills  the  test  of  uniformity,  in  this  instance  rather  a test  of  the 
mixing  than  anything  else. 

Whenever  the  riffle  cutter  has  been  tested  under  proper  conditions 
it  has  given  admirable  results;  it  is,  accordingly,  strongly  recom- 
mended wherever  it  can  be  used.  The  prospector  and  miner  will  find 
riffles  both  cheap  and  handy.  Riffles  can  be  used  wherever  cone  and 
quarter  sampling  or  split  shovel  sampling  is  now  used.  The  utmost 
use  of  riffles  will  tend  toward  uniformity,  low  cost,  rapidity,  and  the 
greatest  possible  precision  in  sampling. 

Drying  the  Sample. — Two  devices  are  in  common  use  in  Montana 
for  drying  ore  samples;  the  most  common  is  the  cabinet  shelf  dryer, 
heated  by  steam  or  electricity;  steam  tables  with  large  flat  tops  are 
also  found  at  most  mills.  The  shelves  of  the  cabinet  dryers  will  accom- 
modate pans  large  enough  to  hold  eight  or  ten  pounds  of  ore  in  a thin 
layer.  Larger  samples  are  divided  among  pans  or  spread  on  the  steam 
table.  An  hour’s  drying  is  usually  considered  enough,  although  the 
sample  may  be  left  in  the  dryer  much  longer  while  awaiting  its  turn 
for  fine  grinding. 

Drying  is  by  far  the  simplest  and  easiest  of  the  four  mechanical 
operations  in  ore  sampling. 

The  drying  problem,  if  indeed  there  is  any,  is  rather  one  of  pro- 
curing a sample  to  dry,  or  taking  the  moisture  sample,  then  drying 
the  sample  after  it  is  procured.  At  some  Montana  mills  the  sample 
for  moisture  is  a composite  made  up  of  several  cuttings  from  different 
places  well  within  the  lot,  at  other  mills  a somewhat  arbitrary  cor- 
rection is  made  to  the  moisture  on  the  regular  mill  sample,  or  on  a 
portion  of  the  last  mill  crushings.  How  to  get  a moisture  sample 
cheaply  and  accurately  is  the  same  sort  of  problem  as  how  to  cheaply 
and  accurately  sample  spotty  gold  ore;  both  are  troublesome. 

CONE  AND  QUARTER  SAMPLING 

There  is  a method  for  sampling  ores,  handed  down  through  many 
decades,  which  is  known  as  the  cone  and  quarter  process  and  is  sup- 
posed to  have  originated  in  Cornwall.  The  ore  is  thrown  into  a 
conical  pile,  which  is  then  spread  out  with  a tool  as  the  operator 


18 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


FIG.  4. — CONE  AND  QUARTER  SAMPLING. 

The  first  cone  is  being  ringed  to  mix  the  fine,  damp  material. 


PROBABILITY  SAMPLING 


19 


circles  about  the  pile.  Quarters  are  marked  and  two  opposite  ones  are 
shoveled  away,  leaving  one-half  of  the  original  lot  as  a sample.  The 
coning  and  quartering  is  repeated  as  often  as  necessary  to  get  the 
right-sized  sample.  Figure  3 shows  the  operation  in  progress  on  a 
steel  sampling  floor. 

The  principle  involved  in  cone  and  quarter  sampling  is  that  of 
symmetry  about  a vertical  axis;  an  additional  and  less  effective 
principle  is  that  of  compensation  of  opposite  quarters.  The  idea  in 
the  cone  and  quarter  method  is  that  the  ideal  pile  shall  be  uniform 
about  the  center,  but,  if  the  pile  is  not  uniform,  the  opposite  sectors 
across  any  given  diameter  may  be  expected  to  compensate  for  each 
other  and  so  establish  a working  average.  The  method  of  dividing  the 
lot  allows  the  principle  of  diagonal  compensation  to  apply  to  both 
sample  and  discard. 

Although  splendid  work  can  be  done  by  the  cone  and  quarter 
method  the  principles  are  not  as  simple  nor  is  the  work  as  independent 
of  human  discrimination  as  sampling  by  other  methods.  An  exag- 
gerated segregation  of  fine  and  coarse  particles  always  occurs  during 
the  coning  of  the  pile;  depending  entirely  on  the  ensuing  distribution 
of  the  finer  core  of  the  pile,  there  may  be  either  a fair  halving  or  a pre- 
ponderance of  values  in  either  sample  or  reject.  Mixing  the  lot  by 
“ringing  about”  before  coning  is  a common  practice  (see  Figure  4). 
The  use  of  crosses  to  help  center  the  pile  and  hold  the  sides  during 
the  division  is  also  common  practice. 

PROBABILITY  SAMPLING 

The  law  of  averages  and  the  theory  of  probability  demonstrate 
that  if  either  single  pieces  or  small  portions  of  a large  lot  are  chosen 
at  random  the  composition  of  the  selection  will  approach,  after 
enough  selections  and  as  a limiting  condition,  the  composition  of  the 
entire  lot.  Obviously,  if  one  selects  the  entire  lot,  the  sample  and  lot 
become  identical.  However,  it  is  not  necessary  to  take  the  entire  lot, 
for  by  mixing  and  taking  a sufficient  number  of  single  particles,  or 
by  making  enough  cuttings,  or  by  a combination  of  mixing  and 
dividing,  it  is  possible  to  take  not  more  than  one-fifth,  one-tenth,  or 
even  one-twentieth  of  the  lot  and  still  get  a truly  representative 
sample.  Shovel  sampling,  split  shovel  sampling,  riffle  sampling,  and 
all  types  of  mechanical  cutters  involve  more  or  less  of  the  proba- 
bility principle. 

To  make  the  probability  overwhelmingly  on  the  side  of  pre- 
cision, a questionable  number  of  divisions  is  not  taken,  but  thousands 
of  divisions,  each  portion  containing  thousands  of  particles,  are  com- 
monly made.  Furthermore,  the  possibility  of  large  pieces  influencing 
the  results  is  precluded,  and  any  influence  that  can  interfere  with 
absolutely  random  division  is  avoided.  Thus  any  influence  which  tends 
to  select  according  to  size,  weight,  shape,  density,  color,  hardness, 
porosity,  or  any  other  imaginable  property  is  eliminated. 


Number  of  Cuttings  for  Sample 


20  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


Actual 

Lead 

Content 


0 10  20  £0  40  £0  60  70  £0  90  100 


Percentage  of  Lead  in  Sample  Selected 

FIG.  5. — PROBABILITY  CURVE  FOB  DISTRIBUTION 
OF  SAMPLING  RESULTS. 


21 


THE  LARGEST  PIECES 

There  is  no  doubt  but  that  the  results  of  sampling  must  follow 
some  probability  curve,  mathematically  determinable  by  the  factors 
and  quantities  involved;  the  engineer  makes  certain  that  the  curve 
shall  be  of  the  shape  indicated  in  Figure  5.  The  curve  means  that, 
depending  on  the  number  of  divisions  or  cuttings  for  sample,  the 
probable  result  will  lie  within  the  extremely  narrow,  vertical  portion 
of  the  blackened  area.  On  this;  basis,  if  one  repeatedly  crushes  between 
divisions  so  as  to  circumvent  the  influence  of  large  single  particles, 
the  limit  of  accuracy  is  not  exceeded,  although  the  crushing  and 
dividing  is  repeated  as  many  times  as  neessary  to  sufficiently  reduce 
the  size  of  the  sample. 

In  actual  sampling  the  sequence  of  crushing  and  cutting  is  com- 
monly performed  from  six  to  ten  times.  Each  portion  of  the  thousand 
or  more  selections  made  by  one  machine  contains  millions  of  particles 
and  the  final  result  has  ever}'  assurance  of  correctness  and  is  capable 
of  proof.  The  proof  consists,  not  in  analyzing  the  entire  lot,  which, 
as  already  stated,  is  impossible,  but  in  repeating  the  process,  in  getting 
duplicate  samples,  or  by  sampling  by  an  entirely  different  method. 

If  a lot  of  ore  weighing  50  tons  requires  60  minutes  to  go  through 
a mill  whose  mechanical  cutters  are  taking  out  a fifth  at  the  rate  of 
60  cuts  a minute  and  are  in  series  of  four,  the  first  cutter  will  make 
3,600  selections  and  take  out  10  tons  containing  millions  of  particles. 
After  crushing,  the  second  cutter  will  make  its  3,600  selections  from 
the  first  sample  and  take  out  its  2 tons  containing  again  millions  of 
particles.  Then  the  third  cutter  will  divide  the  2-ton  lot,  making  its 
3,600  selections  and  taking  out  800  pounds  containing  again  some 
millions  of  particles.  The  last  cutter  will  divide  the  800  pounds  and 
with  its  3,600  selections  take  out  160  pounds  in  another  sample  like- 
wise containing  millions  of  particles.  The  process  of  crushing  and 
dividing  is  then  continued  with  suitable  machines,  and  usually  in  the 
bucking  room,  until  the  final  analysts’  packets,  each  containing  millions 
of  particles,  represents  the  original  lot  with  the  same  precision  as 
that  of  any  previous  larger  selection  or  sample. 

THE  LARGEST  PIECES 

The  goal  to  be  attained  in  the  most  economical  crushing  and 
dividing  is  to  crush  the  larger  particles  no  more  than  necessary  to 
prevent  their  one-sided  composition  affecting  the  accuracy  of  the 
results.  The  limiting  size  of  particle  is  of  course  a constant  depending 
on  the  nature  of  the  material  and  the  quantity  of  the  lot.  The  earlier 
sampling  mills  in  the  western  United  States  were  strongly  constrained 
to  crush  as  little  as  possible,  because  the  ore  was  desired  coarse  for 
blast  furnace  smelting.  The  combined  considerations  of  economy 
and  preserving  the  ore  coarse  have  given  us  most  of  the  mill  charac- 
teristics which  are  found  in  western  samplers.  The  mills  have  been 
built  and  operated  largely  on  an  empirical  basis,  with  thorough  studies 
on  the  vital  factors  conspicuously  absent.  The  limiting  sizes  for 


22 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


different  ores,  minerals,  and  weights  of  lot  is  one  of  the  studies  on 
which  comparatively  little  work  has  been  done  in  a systematic  way. 

In  a general  way,  and  as  far  as  practicable,  the  present  sampling 
mills  are  constructed  to  so  crush  the  larger  pieces  that  when  a division 
is  made  there  shall  be  no  excessively  large  pieces.  An  excessively  large 
piece  is  one  which  would  materially  affect  the  result,  depending  on 
whether  it  enters  the  sample  or  the  reject.  The  mills  are  intended  to 
make  thousands  of  what  may  be  termed  the  largest-sized  pieces.  A 
few  of  the  larger  pieces  cannot,  then,  by  getting  in  the  wrong  division, 
appreciably  affect  the  result. 

Some  investigators  have  supposed  that  the  law  of  averages  would 
apply  to  the  larger  pieces  in  this  way,  that  even  if  some  excessively 
large  and  rich  pieces  should  tend  to  increase  the  values  in  the  samples 
there  would  be  enough  large  lean  pieces  to  conterbalance.  Weld1,  in 
1910,  clearly  demonstrated,  by  actual  tests,  that  it  is  not  admissible 
to  use  this  interpretation  of  the  probable  distribution  of  results.  A 
probability  curve  based  on  the  average  obtained  by  balancing  a few 
large  and  individually  important  quantities  would  be  much  broader 
and  flatter  than  the  curve  indicated  in  Figure  5. 

The  accuracy  of  the  sampling  operation  is  jeopardized  in  two  ways 
by  the  presence  of  unsuitably  large  pieces;  the  presence  of  the  piece 
affects  the  results,  and  it  interferes  with  the  work  of  the  dividers. 
The  common  occurrence  of  pieces  larger  than  intended  is  commented 
upon  by  Woodbridge2  in  his  paper  on  western  sampling  practice. 

In  1895,  Brunton3  published  a paper  containing  an  extensive  dis- 
cussion on  the  safe  size  of  the  largest  pieces  for  lots  of  ordinary  ores 
and  low-grade  gold  ores.  Woodbridge4  gives  a table,  based  partly  on 
Brunton’s  work  and  partly  on  experiments  and  practice,  designating 
the  smallest  permissible  weight  of  sample  for  different  sized  material. 
If  it  is  necessary  to  have  at  least  a certain  amount  of  material  for 
pieces  of  a given  size,  the  converse  statement  must  also  hold,  that  if 
a lot  of  ore  weighs  only  a given  amount,  then  the  largest  pieces  must 
have  only  the  corresponding  size. 


1 Weld,  “Accuracy  in  Sampling1,”  J.  Ind.  Eng.  Chem.,  Vol.  2 (1910),  page  426. 

2 Woodbridge,  T.  R.  ; *'Cre-Sampling  Condition  in  the  West.”  U.  S.  Bureau  of  Mines, 

Technical  Paper  86,  page  57  (1916). 

8 Brunton,  D.  W.  ; “The  Theory  and  Practice  of  Ore-Sampling.”  Trans.  Am.  Inst.  Min. 
Engrs.,  Vol.  XXV.,  page  826  (1895). 

4 loc.  cit. 


The  table,  as  given  by  Woodbridge,  follows: 


HIGH  VALUE  MINERALS 


23 


Smallest  Permissible  Weight  of  Sample 
for  Varying  Sizes  of  Crushing 

Smallest  Permissible 


When  Crushed  To — Weight,  Pounds 

Two  inches  10,000 

One  and  one-half  inches ~ 5,000 

One  inch  - - - 2,000 

Three-fourths  of  an  inch 1,000 

One-half  inch  400 

Three-eighths  of  an  inch 300 

One-fourth  inch  200 

Three-sixteenths  of  an  inch 100 

One-eighth  of  an  inch 75 

Six-mesh  ... + — ~ 50 

Ten-mesh  25 

Eighteen-mesh  10 

Thirty-mesh  4 

Fifty-mesh  1 


Woodbridge  applies  the  table  to.  ordinary  gold  ores  and  suggests 
that  the  limits  may  be  too  restricted  for  low-grade  silver  ores.  The 
relationships  expressed  in  the  table  may  well  be  adhered  to  for  the 
sake  of  allowing  a reasonable  margin  of  safety.  The  common  presence 
of  ore  pieces  larger  than  the  allowable  size,  frequently  seen  in  Montana 
practice,  is  a condition  which  can  be  excused  only  because  of  the  com- 
paratively low  grade  of  the  ores. 

HIGH  VALUE  MINERALS 

The  influence  of  pieces  of  coarse  gold  in  a lot  of  ore  is  so  over- 
whelming as  to  make  any  table  of  quantity-size  relationships  of  little 
value.  Oxidized  surface  gold  ores  and  quartz  containing  coarse  gold 
are  in  places  so  rich  that  single  pieces  may  easily  vitiate  the  sample 
by  whole  ounces.  Accurate  sampling  of  such  materials  demands  that 
the  entire  lot  should  be  finely  ground  before  dividing.  It  is  usually 
admitted  that  ordinary  sampling  mills  are  not  adapated  to  sampling 
ores  contaning  coarse  gold;  it  is  also  obvious  that  it  would  not  pay 
custom  plants  to  install  fine-grinding  machinery  for  the  small  and 
infrequent  lots  of  “spotty”  ores. 

The  prospector  or  miner  who  is  getting  out  rich  material  and 
thinks  he  is  not  getting  fair  returns  can  install  a small  grinding 
machine  and  daily  reduce  to  20-  or  40-mesh  the  few  hundred  pounds 
of  ore  he  produces.  A suitable  grinder  need  not  cost  over  $200.00,  and 
with  whatever  power  is  available  the  small  operator  should  be  able 
to  pulverize  his  high-grade  ore  so  that  any  good  method  of  sampling 
will  give  accurate  results. 


24 


MONTANA . STATE  BUREAU  OF  MINES  AND  METALLURGY 


EQUIPMENT  FOR  SAMPLING 

Several  really  difficult  and  obstinate  conditions  are  met  in  the 
satisfactory  execution  of  the  principles  of  sampling,  so  that  to  do  the 
work  quickly,  cheaply,  and  above  criticism  demands  high  engineering 
accomplishment.  Modern  precision  and  modern  standards  are  always 
becoming  more  exacting,  and  although  the  last  few  years  have  brought 
few  changes  in  the  industry,  there  is  yet  opportunity  for  further  work. 

CRUSHING  AND  GRINDING 

The  following  machines  are  about  the  only  ones  used  in  sampling 
plants  to  reduce  the  size  of  ore  particles: 

a.  Gyratory  rock  breakers — for  the  largest  sizes. 

b.  Jaw  crushers,  Blake  type — for  large  and  medium  sizes. 

c.  Rolls — for  intermediate  and  small  sizes. 

d.  Bell-type  grinders — for  small  and  finest  sizes. 

e.  Disk  grinders — for  the  finest  sizes. 

f.  Bucking  boards — for  the  finest  sizes. 

Baby  gyratories  and  chipmunk  crushers  are  now  and  then  seen  in 
laboratories,  but  their  place  is  for  special  samples  rather  than  for 
routine  samples  of  large  lots. 

The  large  crushers  used  in  sampling  works  are  always  commercial 
mill  units.  The  practice  is  a great  convenience  to  the  sample  mill 
designer,  but,  as  already  mentioned,  the  ordinary  ore  crushers  are  not 
perfectly  adapted  to  sampling,  because  it  is  possible  for  flat  and 
rather  large  pieces  to  get  through  the  crushers  without  suitable 
reduction.  Single  pieces  entering  a spring  roll  may  be  suitably 
crushed,  but  if  several  pieces  enter  together,  or  within  a wave  of  fines, 
one  or  more  pieces  may  fail  to  he  crushed  because  the  rolls  opened 
under  the  strain. 

The  wrear  of  the  hard  iron  working  surfaces  is  usually  compensated 
by  adjusting  the  opening,  but  the  channeling  of  the  jaws  and  the 
corrugation  of  roll  shells  takes  place  just  as  in  any  concentrating 
mill.  As  the  sampling  mills  do  not  contain  sizing  and  returning 
equipment  unless  for  some  additional  function  of  the  mill,  it  follows 
that  samples  frequently  contain  pieces  far  too  large  for  the  size  of 
the  sample. 

The  introduction  of  abraded  iron  into  the  sample  during  the  fine 
grinding  is  a matter  upon  which  data  is  apparently  rather  scanty. 
Fieldner1  reports  that  the  ash  in  five  samples  of  coke  was  increased, 
on  the  average,  2.9%  by  grinding  on  a bucking  board  instead  of  in  a 
pebble  mill.  The  quartz  used  in  the  author’s  mixing  test  contained 
only  0.03%  iron  extractable  from  the  small  rounded  grains,  but  3.17% 
iron  after  grinding  in  the  disk  grinder. 


1 Fieldner,  A.  C.  : “Notes  on  the  Sampling  and  Analysis  of  Coal.”  LT.  S.  Bureau  of 
Mines,  Technical  Paper  76,  page  57  (1914). 


SPLIT  SHOVEL  SAMPLING 


FIG.  «. — SPLIT  SHOVEL  SAMPLING. 

The  sample  man  is  sliding  tile  reject  into  pans;  the  sample 
is  held  In  the  pockets  and  will  he  piled  and  again  divided. 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


DIVIDING  INSTRUMENTS 

The  Hand  Shovel. — The  division  of  a lot  of  ore  into  sample  and 
reject  by  shoveling  it  over,  and  putting  every  fifth  or  tenth  shovelful 
aside  as  the  sample,  is  an  old  and  useful  method  of  sampling.  The 
size  of  the  pieces  and  the  richness  of  the  minerals  must,  of  course, 
correspond  with  the  lot  size,  while  the  restricted  number  of  selections, 
infers  that  the  lot  has  received  some  mixing. 

There  are  evidently  1,000  selections  made  for  sample  if  a 50-ton 
lot  of  ore  is  hand  shoveled  in  10-pound  shovelfuls,  and  every  tenth 
one  is  put  to  one  side  as  the  sample.  As  the  size  of  the  sample 
decreases  the  number  of  selections  gets  critically  small,  but  is  in  a 
measure  compensated  for  by  the  mixing. 

The  method  of  shovel  sampling  is  easily  carried  out  if  the  material 
has  to  be  moved  by  hand  and  is  fine  enough.  Crushing  must  be  intro- 
duced at  the  required  stage  if  the  material  is  not  fine  to  start  with. 
It  is  a common  practice  to  shovel  sample  for  the  first,  or  first  two 
divisions,  and  finish  with  the  cone  and  quarter  method. 

For  nearly  all  large  scale  metallurgical  work  shovel  sampling  is 
far  too  slow  and  costly;  the  method  also  suffers  because  of  the  care- 
lessness of  the  workmen  and  because  of  an  undesirable  element  of 
judgment  in  handling  lots  of  mixed  sizes. 

The  Split  Shovel. — The  split  shovel  is  in  common  use  in  some  of 
the  Montana  sampling  plants.  It  offers  a convenient  means  of 
dividing  a lot,  but  the  number  of  independent  cutting  which  can  be 
made  is  small.  It  makes  no  difference  how.  few  selections  are  made 
if  a lot  of  ore  is  well  mixed,  but  in  practice  it  is  nearly  always  easier 
to  make  many  cuts  than  it  is  to  mix  the  ore.  Figure  6 shows  a sample 
man  sliding  the  reject  from  a split  shovel  into  discard  pans.  Material 
remaining  in  the  closed  pockets  of  the  shovel  will  be  piled  and  cut 
again. 

Riffle  Cutters. — The  widely-used  Jones  type  of  riffle  sampler,  built 
either  as  a floor  stand  or  in  table  size,  is  a remarkable  instrument  for 
dividing  and  mixing  ore  samples.  Suitable  designs  have  from  16  to  40 
slots,  are  rigidly  made,  and  have  the  slots  wide  enough  to  safely 
accommodate  the  particles  poured  over  them.  The  ratio  of  4 to  1 
is  generally  considered  a safe  one  with  which  to  express  the  “width 
of  opening”  over  “diameter  of  particle”  relationship.  This  ratio  is 
usually  greatly  exceeded  when  riffling  small  sizes  and  is  often  far 
from  being,  attained  when  riffling  coarse  material.  The  instrument 
well  deserves  to  be  given  both  more  variety  in  manufacture  and  more 
use  in  the  industries. 

Figure  2 shows  the  26-slot  stand  cutter  used  at  the  Montana  State 
School  of  Mines.  Figure  7 shows  a riffle  with  alternate  bottoms 
closed,  but  as  the  cutter  is  fixed  on  a sharp  slope  it  is  a Jones  riffle 
to  all  intents  and  purposes;  this  cutter  is  in  use  in  several  Montana 


■INCLINED  TABLE  RIFFLE. 


28  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


FIG.  8. — CORNER  IN  EAST  HELENA  RI  CKING  ROOM. 

Hoicking-  boards,  scales,  riffles,  cabinet  dryer,  sieves,  and  sample  holders  can  1m 

seen. 


PIPE  SAMPLING 


29 


mills.  In  Figure  8 is  seen  a neat  table  riffle  at  the  very  left  of  the 
picture;  this  design  is  in  use  at  the  mills  of  the  American  Smelting  & 
Refining  Co.  at  East  Helena,  Montana. 

Pipe  Samplers. — Pipe  samplers  have  long  been  used  in  Montana 
and  in  other  sections  of  the  country,  notably  at  the  zinc  mines  in 
Missouri  and  Oklahoma,  where  the  cars  of  concentrates  are  sampled 
with  the  “gun,”  as  the  pipe  sampler  is  there  called,  immediately  after 
loading  out  for  the  smelters.  Since  the  advent  of  flotation  concen- 
trates, which  are  notoriously  sticky  and  difficult  to  handle,  pipe 
samplers  have  greatly  increased  in  utility  in  the  Butte  district. 

Ore  suitable  for  pipe  sampling  consists  of  concentrates  or  other 
fine  material  which  has  been  produced  in  a regular  and  uniform 
manner,  or  has  been  mixed  in  handling.  Flotation  concentrates  may 
very  in  consistency  from  a thin  mud  to  a dry  powder.  When  sampling 
carloads  of  the  muddy  concentrates  men  are  sometimes  barely  able 
to  support  themselves  on  the  drying  crust.  Cars  which  have  traveled 
long  distances  may  have  the  load  so  firmly  packed  that  an  auger, 
rather  than  a pipe,  is  required  to  cut  out  the  samples. 

According  to  the  Montana  practice,  lots  of  concentrates  are  sampled 
at  the  mill  by  the  shipper  and  later  at  the  custom  sampling  plant,  or 
smelter.  Data  as  to  agreement  of  assays  is  not  available,  but  results 
are  said  to  be  wholly  satisfactory. 

Pipe  sampling  of  a carload  of  concentrates  usually  begins  at  one 
end  of  the  car,  where  a row  of  holes  two  feet  apart  and  two  feet 
from  the  end  wall  is  made;  a parallel  row  is  then  punched  two  feet 
nearer  the  center  and  this  is  repeated  until  samples  are  taken  in  a 
systematic  order  over  the  entire  length  of  the  car  from  points  about 
two  feet  apart.  Hopper-bottomed  cars  have  the  two  deep  pits,  which 
are  hard  to  penetrate,  but  the  pipes  are  long  enough  to  touch  the 
steel  bottoms,  as  in  the  shallowed  portions  of  the  car. 

Pipes  are  commonly  four  to'  five  feet  long,  three  inches  diameter 
at  the  top  and  two  inches  at  the  cutting  edge.  For  firm  materials, 
easily  cleared,  circular  tubes  are  used;  for  sticky  loads  the  pipe  is 
slotted  and  provided  with  a scraper  with  which  the  sample  man  quickly 
forces  the  core  out  into  the  sample  pan.  A sample  of  250  pounds 
weight  is  usually  obtained  by  from  40  to  75  insertions  of  the  pipe. 
Figure  9 shows  three  men  sampling  a car  of  flotation  concentrates 
at  the  Washoe  Sampler. 

Pipe  sampling  of  the  fine  concentrates  may  continue  in  the  bucking 
room  until  the  final  samples  for  moisture  and  assay  are  taken.  The 
sample  man  merely  goes  over  the  pans  of  first  sample  with  a smaller 
pipe,  a foot  long  and  an  inch  in  diameter,  and  punches  from  all  parts 
of  the  pans  enough  cores  to  give  a sample  of  the  required  weight. 

The  justification  of  pipe  sampling  clearly  depends  on  the  uni- 
formity of  the  lot  of  ore  as  it  is  spread  in  the  bin  or  car.  To  test  the 
uniformity  of  a lot  of  concentrates  in  a railroad  car,  the  author  took 


30 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


KICL  9 PIPE  SAMPLING  OF  FLOTATION  PRODUCT. 


PIPE  SAMPLING 


31 


40  four-ounce  grab  samples  from  the  pipes  as  a car  of  flotation  con- 
centrates was  being  sampled  at  a custom  plant.  Each  of  the  samples 
was  dried,  ground,  mixed,  and  analyzed  for  iron  with  the  following 
results : 


Sample 

%Fe 

Sample 

%Fe 

Sample 

%Fe 

Sample 

%Fe 

1 

...14.7 

11 

...14.1 

21 

...13.4 

31 

...14.8 

2 

...14.2 

12 

...14.8 

22 

15.5 

32 

...16.2 

3.. 

...13.8 

13 

...14.5 

23 

....13.1 

33 

...15.7 

4 

...14.5 

14 

— 13.8 

24 

....13,1 

34 

...16.3 

5 

...14.0 

15 

...14.5 

25 

....13.1 

35 

...17.2 

6 

...14.2 

16 

...14.1 

26 

18.3 

36 

-15.4 

7 

...14.3 

17 

...13.2 

27 

....13.8 

37 

...14.8 

8 

...14.1 

18 

...13.6 

28 

....14.5 

38 

...15.3 

9 

...15.0 

19 

...12.8 

29 

...14.8 

39.. 

-17.4 

10 

...13.0 

20 

15.0 

30 

15.0 

40 

...14.3 

The  average  of  all  the  figures  is  14.7%,  and  the  average  deviation 
of  a single  analysis  is  only  .9%  from  the  14.7%.  In  other  words,  the 
average  deviation  from  the  mean  is  approximately  1 part  in  15.  From 
the  sampling  point  of  view  it  means  that  one  could  take  a grab  sample 
anywhere  in  the  car  and  the  probable  analysis  of  that  sample  would 
be  accurate  to  better  than  1 part  in  15. 

The  main  pipe  samples,  from  which  the  little  samples  just  discussed 
were  taken,  weighed  25  to  30  times  as  much  and  were  piled  and  again 
piped  before  drying,  mixing,  and  grinding  for  the  regular  sample.  The 
main  sampling  work  might  reasonably  be  expected  to  be  10'  times  as 
accurate  as  the  author’s  grab  sampling,  which  would  make  the  main 
pipe  sampling  accurate  to  more  than  1 part  in  150,  a precision  consid- 
erably greater  than  ordinary  assaying  or  wet  chemical  analysis. 

Pipe  sampling  of  fine,  mixed  materials  is  very  rapid  and  cheap; 
the  test  confirms  the  prevalent  opinion  that  it  is  also  accurate. 


The  Brunton  Vibratory  Cutter. — One  of  the  earliest  sample  cutters 
used  in  western  sampling  mills  consists  of  a thin  wedge  of  steel  plates 
riveted  to  a shaft  and  set  in  the  center  of  the  ore  stream  as  it  flows 
from  a spout.  The  thin  wedge  has  the  shaft  inclosed  along  its  base 
and  points  upward  into  the  ore  stream;  by  turning  the  wedge  to  one 
side  or  the  other  it  deflects  the  entire  ore  stream  first  to  one  side, 
then  to  the  other  side;  separate  spouts  catch  the  two  ore  streams 
made  by  the  deflector.  Spill  is  taken  care  of  by  steel  wings  on  each 
side  of  the  wedge  or  blade.  The  sample  can  be  made  any  fraction  of 
the  lot  by  the  relative  periods  the  deflector  remains  pointing  toward 
either  sample  or  discard  spout.  Pins  on  a rotating  disk  engage  a cam 
at  the  far  end  of  the  shaft  and  so  throw  the  blade,  first  to  one  side, 
then  to  the  other;  by  the  adjustment  of  the  pins  in  holes  around  the 
edge  of  the  disk  the  periods  are  determined  and  the  periods,  in  turn, 
determine  the  fraction  selected  for  sample. 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLUROV 


32 


FIG.  10 BR UNTON  VIBRATORY  CUTTER  BLADES. 

Two  sizes  as  used  in  one  of  the  East  Helena  Sampling  Mills. 


FIG.  11 MECHANISM  OF  BRUNTON  OSCILLATORY  SAMPLER. 

A crank  arm  on  a disk  changes  the  rotary  motion  of  a pulley  to  the  oscil- 
lations of  the  cutter. 

(After  Brunton.  Trans.  Am.  Inst.  Min.  Engrs.,  1909.) 


1 

i 


; 

i 

i 

I 


BRUNTON  OSCILLATORY  SAMPLER 


33 


FIG.  12. — FIRST  SAMPLER  AND  ROLLS  AT  THE  WASHOE  SAMPLER. 

The  steel  housing-  in  front  of  the  oscillator  is  turned  down  to  expose  the 
parts.  The  sample  drops  through  the  opening  and  falls  to  the  rolls,  the 
reject  is  deflected  away  to  a spout  to  the  conveyor  behind  the  rolls. 


34 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


Two  sizes  of  Brunton  vibratory  cutter  blades  are  seen  in  Figure 
10;  they  happen  to  be  spare  parts  for  the  machines  now  used  in  only 
one  mill  in  Montana. 

The  vibratory  cutter  slips  through  the  ore  stream -quickly,  which 
is  always  an  advantage;  the  blade  also  cuts  the  stream  in  the  same 
direction  for  sample.  If  the  repeated  cutting  in  the  same  direction  is 
considered  a disadvantage,  it  is  eliminated  in  the  Brunton  oscillatory 
cutter,  which  is  next  described.  The  driving  mechanism  of  the  vibra- 
tory cutter  would  doubtless  have  been  further  perfected  if  the  oscil- 
latory cutter  had  not  been  invented. 

The  Brunton  Oscillatory  Cutter. — In  the  States  of  Colorado,  Mon- 
tana, Nevada,  and  Utah  are  many  sampling  mills  built  after  the  Taylor 
and  Brunton  design  and  equipped  with  the  Brunton  “time-sampler”, 
or  oscillatory  cutter.  The  general  scheme  of  the  driving  machanism 
is  plain  after  studying  Figure  11,  while  a cutter  is  seen  in  place  in 
Figure  12. 

The  cutter  is  of  the  general  intersecting  saucer  type,  but  the 
machine  oscillates  back  and  forth  across  a 120°  arc  and  its  cutting 
edges  enter  the  ore  stream  first  from  one  side,  then  from  the  other, 
instead  of  always  from  the  same  side.  The  small  sample  cut  is  plainly 
made  by  a division  of  the  stream,  the  deflecting  planes  entering  first 
from  one  side,  then  from  the  other.  The  division  of  the  ore  stream  is 
smooth  and  clean-cut,  while  the  driving  mechanism  is  noiseless  and 
lasting.  The  wearing  parts  of  the  oscillatory  cutter  are  the  edges  of 
the  sample  segment  and  the  floor  of  the  larger  reject  casting;  the 
small  sample  casting  can  be  frequently  renewed  at  slight  expense, 
thus  maintaining  the  cutting  edges,  while  the  larger  casting  is  renewed 
as  often  as  worn  out. 

The  East  Butte  Cutter. — Figure  13  illustrates  the  mechanical  cutter 
used  at  the  East  Butte  mill.  It  rotates  in  a horizontal  plane  and  is 
obviously  of  the  intersecting  saucer  type.  The  unit  seen  in  Figure  13 
has  4 sample  openings  and  would  make  a 20%  selection,  the  units 
actually  in  place  in  the  mill  have  2 openings  and  make  about  10% 
selections.  The  cutters  are  entirely  suspended  from  above  and  the 
ore  stream  enters  them  either  vertically  or  at  a steep  angle. 

The  Vezin  Cutter. — The  Vezin  type  of  mechanical  cutter  is  made 
in  several  modifications  of  the  original  intersecting  cone  type.  In  all 
forms  the  lower  cone,  either  real  or  imaginary,  is  extended  upward 
on  two  opposite  arcs  in  a sort  of  wing  design;  it  is  into'  the  rotating 
wings  that  the  sample  falls  and  is  discharged  through  the  restricted 
lower  apex  of  the  cone.  It  is  well  to  compare  this  machine  (Figure 
14)  with  the  East  Butte  cutter  and  note  that  both  are  closely  related; 
by  merely  altering  the  relative  sizes  of  the  parts,  the  sample  or  the 
discard  is  made  to  fall  through  the  apex  of  the  inverted  cone. 


EAST  BUTTE  SAMPLEli 


35 


FIG.  13 EAST  BUTTE  TYPE  OF  SA3IPUER. 

This  cutter  has  four  slots;  the  cutters  installed  have  only  two  slots. 


30 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


FIG.  14. — VEZIN  SAMPLER. 

Several  modifications  of  the  type  are  in  com- 
mon use.  This  is  the  Resign  supplied  by 
Traylor  Fug.  & Mfg.  Co. 

The  Snyder  Sampler. — A slotted  saucer,  rotating  on  a horizonal 
axis,  forms  the  base  idea  of  the  Snyder  sampler.  A sloping  feed  spout 
neatly  directs  the  stream  of  ore  through  the  inclined  opening  as  the 
sample  slot  passes.  The  similarity  to  the  several  other  intersecting 
saucer  types  is  apparent  from  Figure  15.  The  machine  usually  has 
two  sample  lots,  as  seen  in  the  picture,  but  the  only  unit  known  to  be 
installed  in  Montana,  which  is  a 28-inch  machine  in  the  ore-dressing 
laboratory  of  the  State  School  of  Mines,  has  a single  slot. 


The  actual  amounts  of  sample  cut  by  the  various  samplers  is  an 
important  topic  which  has  not  been  thoroughly  investigated.  The 
only  data  which  the  author  has  seen  are  figures  obtained  by  the 
Anaconda  Copper  Mining  Company.  These  figures  indicate  that,  in 
their  mills,  considerably  less  than  the  expected  amount  is  selected. 

The  uniformity  of  the  ore  stream  on  entering  the  cutter  is  a large 
factor  in  the  constancy  of  the  fraction  cut  for  sample.  The  mixing 
and  retarding  drums  at  the  East  Butte  mill  give  an  exceptionally 
uniform  feed  to  the  cutters  and  the  fraction  cut  out  is  reported  to  be 
practically  constant. 


SNYDER  DISK  SAMPLER 


37 


FIG.  15 TWO-SLOT  SNYDER  SAMPLER, 

The  saucer  rotates  in  a vertical  plane. 


38 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


A careful  inspection  of  the  relative  sizes  of  cutter  openings  and 
ore  pieces  shows  that  the  ratio  of  4 is  not  often  attained  in  the  case 
of  the  first  cutters.  It  is  believed  that  attention  to  this  detail  will  add 
to  the  perfection  of  future  mills. 

The  number  of  cuts  made  by  mechanical  cutters  is  sometimes  in- 
sufficient for  accurate  work,  especially  if  the  lot  is  hurried  through 
the  mill.  The  difficulty  with  speeding  up  cutters  is  the  batting  and 
scattering  action  on  the  larger  pieces  as  the  velocity  of  the  machine 
increases.  Many  cutter  designs  are  already  on  the  market,  but,  if  it 
should  be  found  desirable  to  make  more  cuts  in  a unit  time,  it  may 
not  be  too  much  to  expect  an  improved  design  for  high  speed  work. 

MIXING  MACHINES 

Henry  A.  Vezin  is  commonly  credited  with  first  having  used  mixing 
and  retarding  drums  in  large  scale  sampling  operations.  He  placed 
staggered  baffles  in  the  drums  to  mix  the  ore  before  it  fell  in  a steady 
stream  to  the  cutter  below. 

The  mill  of  the  East  Butte  Copper  Mining  Company,  at.  Butte, 
Montana,  has  two  mixing  and  retarding  drums  (see  Figure  16)  before 
the  second  and  third  cutters,  respectively.  Thus,  as  the  first  cutter  is 
fed  by  the  main  ore  stream,  all  three  cutters  are  fed  with  a decidedly 
well-mixed  and  uniform  stream  of  ore. 

The  other  Montana  mills  depend  largely  on  shaking  feeders  to 
mix  and  spread  the  samples,  which  one  cutter  delivers  to  the  next.  A 
revolving  disk  is,  however,  found  in  the  No.  2 mill  at  East  Helena, 
between  two  Vezin  cutters;  this  feeder  gives  an  especially  uniform 
feed  to  the  lower  Vezin. 

Retarding  machines  are  highly  desirable  to  elongate  and  equalize 
the  ore  stream  after  a cut  has  been  made.  Natural  spreading  in  the 
short  spouts  does  not  give  a smooth  ore  flow  to  either  rolls  or 
cutters.  Synchromatic  gaps  and  irregular  fractions  are  naturally 
greatest  when  the  stream  equalization  is  least.  Aside  from  the  equal- 
izing for  rolls  and  cutter,  any  mixing  of  the  material  may  be  con- 
sidered an  incidental  matter  if  the  number  of  selections  by  each 
machine  amounts  to  more  than  a thousand,  and  the  values  in  the 
large  and  rich  pieces  do'  not  exceed  the  limits  for  accuracy.  The 
mixing  of  the  ore  stream  is,  however,  an  assurance  of  correct  results 
if  the  number  of  cuts  is  reduced  to  only  a few  hundred. 

It  may  not  be  out  of  place  here  to  analyze  just  what  happens  on 
mixing  a small  lot  of  ore  with  the  riffle  cutter.  We  will  suppose  that 
a lot  is  poured  over  a 30-slot  riffle  with  501  shakings  to  and  fro,  the  two 
halves  are  then  united  and  the  pouring  repeated;  the  entire  operation 
of  cutting  and  uniting  is  continued  until  it  has  been  done  10  times. 

The  slots  divide  the  sample  into  30x50,  or  1,500  portions,  at  each 
pouring.  The  1,500  portions  are  not  superimposed  but  are  spread  out 
into  50  layers  at  each  pouring;  when  the  halves  are  joined  the  50 
layers  from  each  side  get  superimposed,  or,  as  may  be  said,  each 


EAST  BETTE  MIXING  DRUM 


89 


gBMi 


PIG.  16 DRUM  MIXER,  SAMPLER,  AND  ROLLS  IN  EAST  BUTTE  MILL 

This  is  the  upper  drum  mixer,  and  the  No.  2 sampler  over  the  No.  2 rolls 


40 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


pouring  puts  the  material  in  100  layers  when  the  halves  are  united. 
On  repeating  the  work  10  times  the  material  clearly  gets  divided  into 
10x1,500  portions  and  the  full  numbers  of  layers  increase  to  10x100, 
or  1,000.  The  100  layers  made  by  the  1,500  portions  at  any  one  pouring 
give  a splendid  lateral  distribution  of  any  inequality,  but  cannot  pos- 
sibly equalize  throughout  the  pulp  any  segregation  in  either  the  first, 
middle,  or  last  of  the  lot  poured.  But  uniting  the  halves  and  repeating 
does  effectually  dispense  the  vertical  segregation,  as  the  inequalities 
in  the  first,  middle,  or  last  of  the  pouring  may  be  called.  Thus,  with 
a few  repetitions,  the  lot  becomes  uniform  laterally  and  vertically,  or 
is  well  mixed.  The  previously  described  test  on  the  quartz  and  iron 
ore  is  very  good  proof  of  the  efficiency  of  riffle  mixing. 

DRYING  MACHINES 

It  has  already  been  mentioned  that  the  Montana  practice  uses  both 
steam  and  electrically  heated  cabinet  shelf-dryers,  as  well  as  large 
steam  tables.  In  all  cases  the  operation  is  very  simple  and  requires 
no  attention.  Although  drying  requires  about  the  same  time  as  mill 
sampling,  it  is,  nevertheless,  so  rapid  and  simple  that  there  is  little 
incentive  to  speed  up  the  process.  Faster  drying  would  inevitably 
demand  higher  and  injurious  temperatures,  as  well  as  moving  parts 
to  the  drying  apparatus.  If  all  oth£r  essential  operations  in  sampling 
were  in  as  satisfactory  a status  as  that  of  drying  it  would  be  fortu- 
nate, indeed. 


SAMPLING  OF  TEST  LOT  BY  STATE  BUREAU 

The  results  of  resamplings  and  check  samplings  have  been  pub- 
lished from  time  to  time,  but  to  test  the  matter  of  sampling  more 
exhaustively  and  at  the  same  time  provide  tangible  evidence  that  the 
custom  mills  in  Montana  are  doing  satisfactory  work,  the  State  Bureau 
acquired  the  use  of  a lot  of  ore  and  had  it  sampled  at  the  three  most 
important  custom  mills. 

The  carload  weighed  a little  over  50  tons,  and  was  from  a Montana 
mine  which  is  producing  a silver-lead  ore  of  considerably  greater 
value  than  the  average  of  the  Butte  mines.  The  ore  was  run-of-mine 
product  and,  like  many  high  sulphide  ores,  more  than  half  of  it  con- 
sisted of  rather  fine  to  earthy  material.  At  least  a quarter  of  the 
material  was  in  lumps  over  two  inches  in  diameter,  and  the  rest  was 
intermediate. 

The  minerals  varied  in  size  and  texture  from  large  pure  grains  to 
fine  intimate  mixtures.  The  mineral  composition  was,  approximately: 

Quartz  30%  Arsenical  tetrahedrite 

Pyrite  25%  (gray  copper  ore)  15% 

Galena  15%  Zinc  blende  5% 

Other  gangue  minerals 


10% 


STATE  BUREAU  TEST  LOT 


41 


The  lot  typified  Montana  ore  of  the  better  sort,  with  commercial 
values  in  gold,  silver,  copper,  and  lead;  an  ore  suitable  for  demon- 
strating the  precision  of  sampling  on  customary  and  average  materials. 

The  lot  of  ore  was  sampled  twice  at  the  Washoe  Sampler,  resulting 
in  two  independent  final  pulps.  The  lot  was  sampled  in  the  No.  1 
mill  at  East  Helena,  using  the  coarse  by-pass;  it  was  tenth-shovel 
sampled  at  East  Helena,  and  then  finally  ground  to  pass  the  2-mesh 
screens  and  again  sampled  in  the  No.  1 mill,  this  time  in  the  ordinary 
way.  The  lot  was  sampled  once  at  the  East  Butte  mill  while  in  the 
coarse  condition,  but  duplicate  portions  were  taken  from  the  mill 
product  before  fine  grinding. 

Six  different  samplings  were  thus  made,  giving  seven  pulps;  three 
different  types  of  mechanical  cutters  were  used  and  once  the  lot  was 
hand-sampled.  The  hand-sampling  was  first  by  the  tenth-shovel 
method,  and  it  was  then  coned  and  quartered  until  the  final  splitting 
for  packets  was  made  with  a table  riffle. 

The  actual  sampling  time  at  the  different  mills  varied;  at  the 
Washoe  Sampler  the  lot  required  20  and  30  minutes  at  each  respective 
sampling;  at  the  East  Butte  mill  50  minutes  were  required  for  the 
sampling;  at  East  Helena  fully  2 hours  were  taken  each  time. the  lot 
was  run  through  the  mill. 

The  final  sampling  at  East  Helena,  after  crushing  to  half-inch  size, 
afforded  a good  standard  test,  since  the  material  was  then  all  in  small 
sizes,  had  undergone  repeated  dispersions  and  retardations  in  the 
mills,  and  was  cut  at  least  3,500  times  by  each  of  the  mill  samplers. 

The  lot  was  sampled  in  the  presence  of  the  author  in  each  instance; 
no  particular  arrangements  were  made  at  the  mills,  nor  was  the 
sampling  carried  out  in  any  way  differently  from  the  routine  pro- 
cedure which  the  author  has  repeatedly  observed  when  he  has  hap- 
pened into  the  mills. 

The  seven  final  pulps  were  analyzed  under  as  nearly  identical  con- 
ditions as  possible  in  the  State  School  of  Mines  laboratories.  Lest  too 
few  results  might  involve  deviations  in  the  chemical  work  instead  of  in 
the  sampling,  the  analyses  were  checked  over  from  6 to  8 times  so  as 
to  furnish  average  figures  for  each  component.  Pulp  inequalities, 
chemical  influences,  and  manipulations  all  introduce  deviations,  which 
repeated  analyses  alone  can  eliminate  so  as  to  show  the  precision  or 
lack  of  precision  in  the  sampling. 


42 


MONTANA  STATE  BUREAU  OF  MIXES  AND  METALLURGY 


The  results  of  the  analytical  work  follow: 


Silver,  oz. 

Gold,  oz. 

Lead, 

Copper, 

Iron, 

Insoluble, 

Sample 

per  ton 

per  ton 

per  cent. 

per  cent. 

per  cent. 

per  cent. 

A ... 

37.8 

.21 

12.73 

1.74 

14.49 

32.58 

B ... 

37.3 

.22 

12.46 

1.69 

14.43 

33.07 

C ... 

37.0 

.23 

12.50 

1.74 

14.46 

32.87 

D ... 

37.9 

.21 

12.64 

1.78 

14.77 

' 32.01 

E ... 

37.3 

.21 

12.64 

1.76 

14.52 

32.83 

F .... 

37.4 

.21 

12.72 

1.70 

14.35 

32.50 

G ... 

37.5 

.22 

12.91 

1.73 

14.72 

32.22 

One  conclusion,  only,  can  he  drawn  from  the  results  in  the  table: 
namely,  that  the  sampling  was  well  done  in  each  instance.  The  differ- 
ence between  the  several  pulps  is  less  than  excellent  analysts  might 
report  on  one  and  the  same  pulp. 

The  individual  items  and  gross  values  of  the  lot  may  be  calculated 
for  each  sampling,  reckoning  silver  at  $1.25  an  ounce,  gold  at  $20.67  an 
ounce,  lead  at  8 cents  a pound,  and  copper  at  18  cents  a pound. 


Deviation 


Sample 

Silver 

Gold 

Lead 

Copper 

Total 

From  Mean 

A 

....$47.25 

$4.34 

$20.37 

$6.26 

$78.22 

$0.44 

B 

...  46.62 

4.55 

19.94 

6.08 

77.20 

0.58 

C 

....  46.25 

4.75 

20.00 

6.26 

77.26 

0.52 

D 

...  47.38 

4.34 

20.22 

6.41 

78.35 

0.57 

E 

....  46.63 

4.34 

20.22 

6.34 

77.52 

0.26 

F 

...  46.75 

4.34 

20.35 

6.12 

77.56 

0.22 

G 

....  46.88 

4.55 

20.66 

6.23 

78.32 

0.54 

The  total  values  range  from  $77.20  to  $78.35,  an  extreme  difference 
of  $1.15;  the  average  deviation  from  the  mean  of  all  the  totals  is  $0.45. 
Ore  producers  should  certainly  be  well  satisfied  with  custom  sampling 
which  shows  this  degree  of  precision. 

MILL  FLOW  SHEETS 

To  indicate  the  treatment  by  which  each  of  the  samples  was 
obtained  in  the  State  Bureau  test,  the  following  flow  sheets  have 
been  prepared. 


WASHOE  SAMPLER  FLOW  SHEET 


48 


Washoe  Sampler — 

Cars  unloaded  over  hopper;  18'x20'xll'  deep 

Shaking  grizzly  feeder;  1.5"x2.0"  holes  in  24"x20"  section 

Crusher;  20"xl0"  opening 

Shaking  tray 

Elevator  to  top  of  mill 

No.  1 cutter;  Brunton  oscillatory,  7.0"xl0.5"  opening,  40  cuts 
per  minute 

Sample;  20%,  or  20,000  lbs.  on  50-ton  lot 
Shaking  tray;  12"  effective  length 
No  1 rolls;  16"x36" 

No  2 cutter;  Brunton  oscillatory,  6.0"x8.0"  opening,  28  cuts  per 
minute. 


Sample;  20%,  or  4,000  lbs.  on  50-ton  lot 
Shaking  tray;  9"  effective  length 
No.  2 rolls;  14"x30" 

No.  3 cutter;  Brunton  oscillatory,  4.5"x6.75"  opening,  63  cuts  per 
minute 

Sample;  20%,  or  800  lbs.  on  50-ton  lot 

Bell  distributor 

No.  3 rolls;  12"  x 24" 

No  4 cutter;  Brunton  oscillatory,  3.5"x5.0"  opening,  68  cuts  per 
minute. 


Sample;  160  lbs.  on  50- ton  lot 
Trolley  bucket 

Steel  sampling  floor  in  bucking  room 
Split  shovel  to  8 to  10  lbs. 


Sample;  8 to  10  lbs. 

Dried  in  shelf  cabinet,  electric  heat 

Engelbach  grinder 

Riffle  cutter;  26  slots,  each  .64"x2.0" 


Sample;  32  ounces 
Braun  disk  grinder 

Hand  sieves;  100,  120,  150,  and  200  mesh 
Rolled  on  pebble-surfaced  oil  cloth  1,000  times 
Sample  split  for  4 packets  with  inclined  riffles 


44  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

East  Helena  No.  1 Mill— 

Cars  unloaded  onto  steel  pan  conveyor;  pans  18"xl8"x6' 
Chute  to  No.  5 McCully  gyratory  crusher 
Belt  conveyor,  16"  belt,  to  top  of  mill,  under  magnet 
Chute  to 


A (fine  grinding  and  sampling) 
Trommels;  12'x60",  y8" x]/s " mesh 


under 

No.  1 cutter;  Vezin,  wings  14"  and 
3"x20",  30  cuts  per  minute 

Sample;  20%,  20,000  lbs.  on  50-ton 
lot 

Shaking  tray;  4'  effective  length 

No.  2 cutter;  Vezin,  wings  7"  and 
1.5"xl0",  34  cuts  per  minute 

Sample;  20%,  4,000  lbs.  on  50-ton 
lot 

Shaking  tray;  4'  effective  length 

Rolls;  12"xl2" 

Shaking  tray;  4'  effective  length 

No.  3 cutter;  Vezin,  same  as  No.  2 
cutter,  40  cuts  per  minute 

Sample;  20%,  800  lbs.  on  50-ton  lot 

Shaking  tray;  3'  effective  length 

No.  4 cutter;  Vezin,  same  as  No.  2 
cutter,  40  cuts  per  minute 

Sample;  20%,  160  lbs.,  on  50-ton  lot 
Locked  sample  hopper 


nr 

over 


2-8eotion  trommel, 
16 T x 36" 

I 

5/8”  x B.5" 
reotangleB 

£" 

circles 

oversiEi 


rolls, 
16"  x 36" 


rolls, 
16"  x 36" 


No.  4 

McCully 

gyratory- 


return  conveyor 
to  top  of  mill 

» 

trommel,  12*  s>  60"| 
3/8"  x 3/8"  screen 

! 1 


through 

i 


overaise 
L— 


Sample;  wheelbarrow  to  steel  sample  floor  in  or  near  bucking 
room 

Cone  and  quarter,  or  riffle  cut,  to  10  to  12  lbs. 

Dried  in  shelf  cabinet  or  on  steam  table 
Bell  grinder 

Hand  sieves;  100,  120,  and  150  mesh 

Table  riffle  to  24  ounces 

Rolled  15  minutes  on  special  paper 

Sample  split  with  table  riffle  to  4,  6-oz.  packets 


EAST  BUTTE  SAMPLING  MILL 


45 


B (coarse  sampling) 
No.  1 Vezin  cutter 


Sample;  20% 

Return  conveyor  to  top  of  mill 


Discard,  out  of  mill  on  conveyor 


Chute  to  No.  2 trommel,  12'x60",  mesh 


under 

No.  2 Vezin  cutter 


2-section  trommel  and  closed 
circuit,  as  above 


over 


Same  as  under  A to  finished  sample 

East  Butte  Sampling  Mill — 

Cars  unloaded  over  mill  hopper 
Shaking  feeder 
Crusher;  12"x24"  opening 
Spout  to  elevator 
Elevator  to  top  of  mill 

No.  1 cutter;  East  Butte,  8"xl2"  openings,  28  cuts  per  minute 

Sample;  10%,  5 tons  on  50-ton  lot 
Shaking  tray;  3'  effective  length 
No.  1 rolls;  16"x36" 

Drum  mixer;  6'x2',  16  r.m.p. 

No.  2 cutter;  East  Butte,  6"x7.75"  openings,  26  cuts  per  minute 
Sample;  10%,  1,000  lbs.  on  50-ton  lot 
Shaking  tray;  3'  effective  length 
No  2 rolls;  10"x24" 

Drum  mixer;  5'x23",  10  r.p.m. 

No.  3 cutter;  East  Butte,  4.5"x5.5"  openings,  16  cuts  per  minute 

Sample;  10%,  100  lbs.  on  50-ton  lot 
Shaking  tray;  3 ' effective  length 
No.  3 rolls;  9"x9" 

Sample  can 

Cast  iron  riffle  cutter  to  15  to  20  lbs. 

Sample;  15  to  20  lbs.  to  bucking  room 
Riffle  cutter  to  8 to  10  lbs. 

Sample  to  shelf  cabinet  or  table  dryer 
Bell  grinder 

Table  riffle  to  16  ounces 

Hand  sieves,  100,  120  and  150-mesh 

Rolled  on  cloth 

Table  riffle;  split  to  4,  4-oz.  packets 


4G  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

SAMPLING  MILLS  IN  MONTANA 

THE  WASHOE  SAMPLER 

The  $150,000  steel-concrete  custom  ore  sampling  plant  of  the  Ana- 
conda Mining  Company  is  known  as  the  Washoe  Sampler  and  is 
situated  on  the  main  line  of  the  Butte,  Anaconda,  and  Pacific  Railroad 
at  Butte,  Montana.  The  main  mill  portion  is  absolutely  fireproof;  it 
was  put  in  operation  in  1911,  after  a fire  had  destroyed  the  previous 
structure.  The  new  mill  was  designed  and  built  by  the  company  engi- 
neers following  the  Taylor  and  Brunton  system,  which  had  been  suc- 
cessfully demonstrated  in  the  first  mill. 

Figure  17  is  a diagram  of  the  Taylor  and  Brunton  system,  which, 
in  a general  way,  is  the  scheme  followed  in  the  present  sampler.  The 
Brunton  oscillatory  time  samplers  are,  of  course,  the  cutters  installed. 
The  types  of  machines  used  and  the  fractions  cut  at  the  several  stages 
have  already  been  indicated  in  the  flow  sheet  of  the  mill,  and  are 
repeated  in  Figure  17.  The  main  machinery  tower  has  floors  35  feet 
by  45  feet;  the  main  elevator  pit  floor  is  28  feet  below  the  ground 
floor,  and  the  ridge  of  the  building  is  68  feet  above,  a total  elevation 
of  96  feet  thus  being  used. 

The  arrangement  of  the  mechanical,  power,  and  switching  facilities 
is  such  that  500  tons  of  ore  can  be  sampled  in  an  8-hour  shift,  and 
1.200  tons  can  be  put  through  in  24  hours.  A 50-ton  lot  has  been 
sampled  in  9 minutes,  but  the  usual  running  time  is  from  20  to  30 
minutes;  if  ore  comes  in  box  cars  the  sampling  depends  on  how  long 
the  unloading  takes. 

Figure  18  shows  a portion  of  the  tracks  serving  the  plant.  After 
weighing  on  the  upper  set  of  Fairbanks  100-ton  recording  beam  scales, 
the  cars  are  lowered  by  cable  to  the  right  hand  side  of  the  mill  and 
unloaded  in  the  shed  over  the  mill  hopper.  As  soon  as  a car  is 
unloaded  it  can  be  pulled  back  with  the  electric  hoist  and  let  down 
on  the  left  side  of  the  mill  to  receive  the  same  lot  of  ore  it  originally 
contained.  On  the  loading  side  of  the  mill  is  a second  scale;  cars 
can  thus  be  switched  from  one  side  of  the  mill  to  the  other  in  a minute 
or  two.  They  can  be  weighed  after  loading  and  then  let  down  farther 
on  the  same  track  for  delivery  to  the  railroad. 

A wagon  and  truck  unloading  shed  is  seen  at  the  right  in  Figure 
18;  below  the  floor  of  the  shed  are  fourteen  50-ton  hoppers  over  a 
conveyor  which  delivers  to  the  mill  hopper.  The  brick  structure  seen 
between  the  tracks  in  the  foreground  of  Figure  18  houses  the.  black- 
smith shop  and  change  room.  Figure  19  shows  how  massive  cast  iron 
pipe  may  be  used  for  permanent  and  tight  spouting  in  mill  equipment. 

The  mill  normally  selects  0.16%  of  the  original  lot  for  the  bucking 
room;  by  using  a special  cam  arrangement  in  the  mechanism  of  the 
second  cutter  only  0.04%  need  be  cut  out.  The  smaller  cut  is  conve- 
nient on  large  lots.  Four  cutters  will  be  used  on  lots  weighing  between 


TAYLOR  AND  BRUXTON  SAMPLING  SYSTEM 


47 


Jst  Cut 

m 400- Lb.  Sample 
From  1 Ton 
Wo  1 Sam  pit 
20%  Sample 

Coarse 
Crushing  Ft  oils 
16x^6  Rolls 
-No.  <2  Sampler 
20%  Sample 

2nd  Cut 
* 30- Lb  Sample 
From  1 Ton 

Fine 

Crushing  Rolls 
14x27  Rolls 
3rd  Cut 
” 16 -Lb.  SacnplG' 

From  J 7on 


Wo  3 Sampler 
20  % Sample 
Sample  Rolls 
t2x20  Rolls 
Line  Shaft 
4th  Cat 
*3.2 -Lb  Sample 
From  1 Ton 
'0.64%  Discard 
' Sample  Safe 
0-/6%  Sample 

/Vo.  -4  Sampler 
20  % Sample 

9 9.  Q4£Di  Oca  nd 
'u  Delivery  TnacF 


FIG.  17 TAYLOR  AND  HRUNTON  SAMPLING  SYSTEM. 

The  \YTaslioe  Sampler  follows  this  general  diagram  closely. 

(After  Brunton,  Trans.  Am.  Inst.  Min.  Engrs.,  1909) 


48 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


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EAST  HELENA  SAMPLING  MILLS 


49 


50  and  12.5  tons.  Smaller  lots  require  less  cutters  in  the  following 
gradations:  on  lots  weighing  from  25,000  pounds  down  to  5,000  pounds 
three  cutters  are  used,  on  lots  weighing  from  5,000  pounds  down  to 
1,000  pounds  two  cutters  are  used,  and  on . lots  weighing  less  than 
1,000  pounds  only  one  cutter  is  used.  The  1 /40th  of  the  entire  lot, 
which  must  be  held  30  days  according  to  the  Montana  law,  is  usually 
the  reject  from  the  third  cutter  on  large  lots;  with  smaller  lots  it 
may  be  the  reject  from  the  fourth  cutter  or  even  the  entire  lot  itself. 

The  frontispiece  shows  that  the  whole  front  section  of  the  mill 
is  merely  a row  of  50-ton  steel  bins;  these  bins  are,  of  course,  avail- 
able for  storing  large  lots  whenever  necessary.  Beneath  the  large  bins 
are  48  small  bins  on  the  ground  floor  of  the  mill,  which  are  in  con- 
tinual use  for  storing  the  ll/40th  portions.  When  the  legal  period  has 
elapsed,  the  reserve  bins  are  emptied  in  groups  and  a composite  lot  is 
run  through  the  mill  and  then  sent  to  the  smelter.  Superintendent 
Margetts  states  that  the  reserve  samples  are  very  rarely  called  into 
service;  whenever  one  is  used  particular  attention  is  given  to  properly 
cutting  down  the  entire  sample  in  the  presence  of  the  shipper.  The 
shipper  is  never  allowed  to  take  a small  grab  sample  for  control  assay. 
When  the  reserve  samples  are  properly  worked  down  to  the  final 
packets,  in  the  same  manner  as  the  original  sample  was,  the  assay 
results  prectically  always  check  the  first  assaying.  Only  in  the  rarest 
instances  is  a complaint  carried  further. 

The  tendency  to  increase  the  fineness  of  grinding  has  been  marked 
in  the  case  of  the  Washoe  bucking  room.  The  80-mesh  sieve  once 
used  has  been  entirely  discarded.  Copper  ores  are  ground  to  pass 
100-mesh,  silver  ores  are  ground  tO'  pass  120-mesh,  high-silver  ores, 
lead  ores,  and  zinc  ores  are  ground  to  pass  150-mesh,  and  high-gold 
ores  to  pass  200-mesh.  The  mill  experience  has  been  that  lead  and 
zinc  ores,  as  well  as  the  rich  gold  ores,  require  the  finer  grinding  for 
satisfactory  chemical  results  on  the  pulps.  If  gold  metallics  are 
encountered  they  are  ground  with  some  of  the  pulp  on  the  bucking 
board  until  everything  passes  the  screen.  Local  experience  is  that 
metallics  in  ores  tributary  to  the  Anaconda  smeltery  easily  yield  to 
disintegration  when  ground  with  sample  pulp;  after  rolling  on  the 
cloth  the  metallics  become  uniformly  dispersed  throughout  entire  pulp. 

THE  SAMPLING  MILLS  OF  THE  AMERICAN  SMELTING  & 
REFINING  COMPANY  AT  EAST  HELENA,  MONTANA 

The  American  Smelting  & Refining  Company  provides  extensive 
sampling  facilities  for  the  custom  ores  which  maintain  its  lead  smeltery 
at  East  Helena,  Montana.  The  smeltery  started  operations  just  30 
years  ago,  and  some  of  the  sampling  mill  construction  dates  from 
about  that  time,  although  many  improvements  and  large  additions 
have  been  made  meanwhile.  The  plant  maintains  three  distinct 
sampling  mills  and  a steel  sampling  floor,  55  feet  by  65  feet  in  the 
clear,  for  cone  and  quarter  sampling. 


50 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


FIG.  J!>. — THIRD  SAMPLER  AND  THIRD  ROLLS  IN  WASHOE  SAMPLER 

This  sot  of  rolls  lias  the  boll  distributor  inside  the  housing*'  over  the  rolls. 
The  pipe  at  the  back  of  the  cutter  carries  reserve  sample  to  the  trolley 
bucket  on  the  first  floor. 


EAST  HELENA  SAMPLING  MILLS 


51 


The  East  Helena  practice  largely  demands  grinding  ores  and  flux 
to  pass  3 /8-inch  mesh  to  meet  the  roasting  requirements.  The  com- 
pany has,  accordingly,  fitted  both  the  No.  1 and  No.  2 sulphide  mills 
to  crush  to  this  fineness  and  then  to  make  the  sample  selections.  The 
fine-grinding  not  only  accounts  for  the  peculiar  flow  sheet  of  the  No.  1 
and  No.  2 mills,  but  consolidates  the  cutters  in  small  space  and  assures 
highly  satisfactory  mechanical  division  for  sample.  The  No.  1 mill 
has  provision  for  either  grinding  the  entire  lot  to  pass  the  3 /8-inch 
mesh  trommels  before  sampling,  or,  after  the  preliminary  crushing  in 
the  big  gyratory,  l|/5th  of  the  lot  may  be  cut  out  with  the  first  sampler 
and  then  reduced  to  pass  the  3/8- inch  screen  on  its  way  to  the  last  three 
samplers.  The  No.  2 mill  is  also  for  sulphide  ores  and  furnace  prod- 
ucts; it  has  no  by-passes  in  its  closed  circuit,  which  grinds  to  pass  a 
5 /16x3 /8-inch  screen  before  sampling  witth  two  machines  in  dose  series. 
Both  the  No.  1 and  No.  2 mills  are  provided  with  excellent  models 
of  the  Vezin  sampler.  The  No.  3 mill  is  for  oxide  ores  and  has  Brunton 
vibratory  cutters.  The  No.  1 mill  delivers  1 /625th  of  the  lot  as  sample; 
both  of  the  other  mills  deliver  l/25th  of  the  lot  as  sample. 

The  No.  1 mill  is  conspicuous  in  that  it  contains  no  elevators;  the 
transfer  and  elevation  of  materials  is  entirely  by  conveyor,  of  which 
there  are  five  in  use.  The  steel  pan  conveyor,  onto  which  all  incoming 
ores  are  unloaded,  is  well  indicated  in  Figure  20.  It  will  be  noticed 
that  the  conveyor  rises  at  the  far  end;  Figure  21  makes  the  nature  of 
this  rise  apparent,  for  in  this  cut  one  sees  that  the  conveyor  enters  the 
building  which  contains  the  No.  5 McCully  gyratory.  After  passing 
the  gyratory,  the  ore  goes  up  the  long  incline  to  the  top  of  the  main 
mill  building.  The  main  building  covers  a space  63  by  30  feet;  the 
structure  is  steel  and  concrete  and  houses  the  equipment  which  has 
been  indicated  in  the  flow  sheet  of  the  mill  on  page  44.  Figure  22 
is  a picture  taken  on  the  ground  floor  of  the  mill;  the  two  16x36-inch 
rolls  and  the  No.  4 McCully  gyratory  are  seen  from  left  to  right  in 
the  foreground,  and  the  sample  cabinet  is  farther  back  to  the  left.  The 
first  Vezin  is  on  the  second  floor  above  the  cabinet,  and  the  three 
Vezin  samplers  following  are  in  this  cabinet  on  the  ground  floor.  The 
two  upper  drawings  of  Figure  23  indicate  the  dimensions,  the  config- 
uration, and  the  spout  approach  to  the  Vezin  samplers  in  the  No.  1 
mill.  The  first  Vezin  makes  30  sample  cuts  a minute,  the  second 
makes  34  a minute,  and  the  last  two  make  40  cuts  a minute. 

The  No.  2 mill  is  a massively-built  wooden  structure,  with  floor 
dimensions  63x36  feet,  built  to  crush  sulphide  materials  to  pass 
5 /16x3/8-inch  rectangles  before  sampling  with  two  Vezin  samplers 
in  tandem.  After  the  mill  feed  passes  the  crusher,  whose  opening  is 
9 by  15  inches,  the  material  is  elevated  and  dropped  to  a 14x27-inch 
set  of  rolls.  The  material  is  again  raised  and  enters  the  trommel  with 
5/16x3/8-inch  openings,  from  which  the  undersize  falls  to  the  Vezin 
samplers  and  the  oversize  to  a set  of  14x26-inch  rolls  in  a closed 
circuit  with  the  trommel.  The  upper  Vezin  makes  35  sample  cuts  a 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


FIG.  20. — UNLOADING  ORE  AT  EAST  HELENA  NO.  1 MILL. 

Steel  pan  conveyor  delivers  to  the  No.  5 McCulIy  gyratory  in  the  shed. 


NO.  1 MILL  AT  EAST  HELENA 


53 


Men  are  unloading  limestone  flux  onto  the  conveyor  to  the  course  crushing  shed. 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


VEZIN  CUTTERS  AT  EAST  HELENA 


55 


A 

/ 


FIG.  23 VEZIN  SAMPLER  WINGS  AT  EAST  HELENA  SAMPLING  MILLS. 

The  two  upper  drawings  are  of  the  cutter  wings  in  the  No.  1 mill;  the  two 
ower  drawings  are  of  the  wrings  of  the  tandem  cutters  in  the  No.  2 mill. 
The  measurements  were  taken  from  the  machines  and  show  satisfactory  design. 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


EAST  BUTTE  SAMPLING  MILL 


57 


minute  and  discharges  onto  a slowly  rotating  circular  plate  feeder, 
which  pushes  out  a uniform  stream  to  the  Vezin  below.  The  second 
Vezin  makes  60  sample  cuts  a minute. 

The  oxide,  or  No.  3 sample  mill,  is  a small  machinery  tower  at 
one  side  of  the  large  steel  sampling  floor  adjacent  to  the  No.  2 sample 
mill.  The  oxide  mill  is  provided  with  two  jaw  crushers,  a set  of  rolls 
and  No.  2 and  No.  3 Brunton  vibratory  cutters.  One-fifth  of  the 
original  lot  is  delivered  as  sample. 

The  steel  sampling  floor  has  a set  of  platform  scales,  a 10x7-inch 
crusher  and  a 12xl2-inch  rolls.  Screens  are  provided  for  breaking  up 
lumpy  ores  and  numerous  crosses  allow  several  hand-sampling  oper- 
ations to  take  place  simultaneously.  Figure  24  is  a view  along  one 
side  of  the  steel  floor;  a cone  of  ore  covered  with  canvas  is  in  the 
foreground,  wooden  crosses  are  along  the  wall,  while  around  the 
entire  room  is  a row  of  covered  bins  to  store  the  reserve  samples. 
The  mills  are  provided  with  58  wooden  reserve  bins  similar  to  those  in 
Figure  24,  and  near  the  No.  1 mill  is  a group  of  42  steel  pockets  for 
the  same  purpose. 

The  East  Helena  mills  are  provided  with  commodious  fine-grinding 
and  finishing  facilities.  The  bucking  room  is  27x57  feet;  it  has  an  all- 
steel  floor  and  the  following  pieces  of  equipment: 

One  Sturtevant,  3"x8",  roll  jaw  crusher 

One  F.  M.  Davis,  12"x20",  rolls 

Two  steam  drying  tables,  each  30"x72" 

Two  Engelbach  type,  fine  grinders 

Three  steel  bucking  boards 

One  round  steel  table,  5'  diameter 

One  cabinet  shelf  dryer,  12  double  shelves 

Two  stand  riffle  cutters,  26,  5/8"  slots  each 

Two  table  riffle  cutters,  36,  5/16"  slots  each. 

The  bucking  room,  as  well  as  each  of  the  mills,  is,  of  course,  pro- 
vided with  pressure  air  for  cleaning.  Ores  are  commonly  ground  to 
pass  100-mesh,  high-silver  ores  to  pass  120-mesh,  and  gold  ores  to 
pass  150-mesh.  Ground  and  sieved  samples  are  rolled  on  a special 
black  surfaced  paper  before  cutting  for  the  final  packets  with  a table 
riffle. 

THE  EAST  BUTTE  COPPER  MINING  COMPANY’S 
SAMPLING  MILL 

The  East  Butte  Copper  Mining  Company  samples  all  of  its  second- 
class  ore  and  custom  ore  in  a mill  adjacent  to  its  smeltery  at  Butte, 
Montana. 

The  mill  building  is  a wooden  structure  some  four  stories  high, 
with  a main  sampling  section  33  feet  long  and  18  feet  wide.  The 
crusher  is  under  the  hopper,  over  which  the  elevated  track  passes 
beside  the  mill.  The  crushed  ore  is  elevated  to  the  first  sampler, 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


FIG.  25. — EAST  BUTTE  SAMPLING  MILL. 

Lots  of  ore  are  received  over  the  “high  line”  above  the  bins  to  the  left.  Outgoing 
cars  may  be  loaded  on  the  receiving  line  or  from  pockets  over  the  depressed 

track  at  the  right. 


SAMPLER  AND  ROLLS  IN  EAST  BUTTE  MILL  59 


FIG.  26. — THIRD  SAMPLER  AND  THIRD  ROLLS  IN  EAST  BUTTE  SAMPLER. 

The  sample  ean  Is  placed  directly  under  the  rolls.  Notice  the  vertical  spout  to  the  sample  saucer,  and  the 

long-  shaking-  trough  from  the  sampler  to  the  rolls. 


60 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


which  is  in  the  top  of  the  mill  over  the  bin  section  which  adjoins 
the  main  machinery  section  of  the  structure.  A conveyor  over  the 
bins  extends  along  the  more  elevated  part  of  the  building  and  allows 
sampled  ore  to  be  dropped  in  any  one  of  the  series  of  Fins,  to  be  sent 
back  to  cars  on  the  high  unloading  line,  or  to  be  screened,  and 
crushed,  and  dropped  in  special  bins.  Figure  25  shows  the  main 
machinery  sections  in  the  center  of  the  picture;  behind  and  to  the 
right  is  the  bin  compartment,  which  is  a story  higher  and  has  the 
series  of  spouts  to  load  cars  on  the  depressed  track.  The  unloading 
line  and  mill  hopper  are  under  the  roof  at  the  left  of  the  picture. 

The  cutters  used  in  the  mill  have  already  been  described  as  the 
East  Butte  type,  and  the  mill  flow  sheet  has  been  indicated  on  page 
45.  The  large  cast  iron  stand  cutter  used  to  finish  the  mill  samples 
ready  for  the  bucking  room,  is  a prominent  piece  of  equipment;  it  is 
the  largest  and  most  substantial  riffle  cutter  in  use  at  any  of  the 
sampling  mills.  Figure  16  gives  an  excellent  idea  of  the  drum  mixers 
and  the  way  they  are  placed  over  the  samplers.  The  final  sampler  is 
pictured  in  Figure  26,  where  it  is  seen  suspended  between  the  spout 
from  the  last  drum  mixer  and  the  shaking  trough  feeding  the  last 
set  of  rolls. 

A peculiar  method  is  used  in  this  mill  for  handling  the  sampler 
rejects.  The  reject  from  the  first  sampler,  which  is  in  the  top  of  the 
mill  under  the  dump  of  the  single  elevator,  is  run  to  final  disposal  as 
the  lot  is  sampled.  The  rejects  from  the  second  and  third  cutters  drop 
to  a hoppered  bin  under  the  first  floor,  from  whence,  after  the  entire 
lot  is  sampled,  they  are  conveyed  to  the  elevator  and  follow  the  rest 
of  the  lot  to  its  final  disposal. 

Compressed  air  is  used  for  cleaning.  The  bucking  room  contains 
the  usual  equipment  for  fine  grinding,  drying,  mixing,  and  dividing. 

THE  SAMPLING  MILLS  AT  ANACONDA,  MONTANA 

The  Anaconda  Copper  Mining  Company  maintains  two  sampling 
mills  in  its  great  smeltery  at  Anaconda,  Montana.  The  mills  are 
almost  exclusively  used  for  sampling  ores  from  its  own  mines,  since 
custom  ores  are  sampled  in  the  Washoe  Sampler  at  Butte. 

Figure  27  shows  the  huge  main  double  sampler.  It  is  probably  the 
largest  sampling  mill  in  the  world,  having  an  8-hour  capacity  of  2,000 
tons.  The  mill  is  constructed  and  operated  in  two  entirely  independent 
but  identical  units.  Most  of  the  ore  handled  comes  from  the  Butte 
mines  and  averages  about  3.2%  copper,  2.5  ozs.  silver,  and  0.01  oz. 
gold.  As  the  ore  runs  fairly  uniform,  the  cut-offs  between  lots  are 
indistinct,  and  the  cleaning  of  equipment  between  lots,  which  is  a 
very  important  feature  in  all  the  other  mills,  is  dispensed  with. 

The  Anaconda  mill  is  of  frame  construction,  with  a sprinkler 
system  for  fire  protection.  The  floor  section  is  45  feet  by  63  feet; 
there  are  four  floors  and  a small  basement  under  the  crushers.  The 
general  mill  scheme  is  given  in  Figure  28,  which  correctly  represents 


ANACONDA  SAMPLING  MILL 


61 


U ¥ I 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


FIG.  28. — DIAGRAM  OF  ANACONDA  SAMPLING  3IILL. 

(Courtesy  of  A.  C.  M.  Co.) 

The  uppermost  elevators  now  deliver  to  conveyors  carrying-  to 
bins  across  the  tracks. 


SAMPLER  AND  CRUSHER  IN  ANACONDA  MILL 


63 


FIG.  20. — FIRST  SAMPLER  AND  SECOND  CRUSHER  IN  ANACONDA 

MILL. 

The  sampler  is  placed  close  to  the  crusher.  The  oscillator  has  a diam- 
eter of  nearly  six  feet,  which  makes  it  by  far  the  largest  cutter  in 

the  State. 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


all  but  the  more  recent  conveyors  from  the  top  of  the  mill  across 
the  tracks  to  the  spouts  delivering  to  the  concentrator  feed  bins. 

The  equipment  is  characterized  by  its  large  size  and  close  spacing 
of  cutters  over  the  next  lower  crushing  machine.  The  latter  feature  is 
well  indicated  in  Figure  29,  which  shows  one  of  the  first  Bruntons 
over  its  8xl8-inch  crusher.  The  mill  also  has  a partial  dust-collecting 
system  with  suction  intakes  at  the  most  dusty  points,  and  a cyclone 
separator  outside  the  building. 

The  bucking  room  is  equipped  with  the  following  units  in  duplicate: 

Engelbach  grinders  Table  riffles;  16  slot 

Braun  disk  grinders  Power  (air)  screens 

Bucking  boards  Cube  mixers;  8"  sides 

Stand  cutters;  26  slot 

Figure  30  is  a splendid  picture  of  the  bucking  room  and  its  equip- 
ment. A 15-horsepower  motor  drives  the  equipment,  while  another 
small  motor  in  the  far  corner  is  coupled  to  a fan  which  exhausts  the 
hood  above  the  two  Engelbach  grinders  and  delivers  the  dust  outside 
of  the  building.  The  room  beyond,  which  is  just  through  the  double 
doors  seen  in  Figure  30,  contains  the  steel  floor  for  split  shovel  work, 
a 10  by  4-inch  jaw  crusher,  moisture  scales,  and  a large  steam  drying 
cabinet. 

The  Southern  Cross  sampling  mill  is  a plant  addition  made  to  the 
smeltery  some  three  years  ago  by  the  company.  The  mill  covers  an 
area  25  by  48  feet,  and  has  four  floor  levels;  it  is  placed  between  two 
columns  and  under  the  ‘‘high  line,”  which  tracks  lead  to  the  main 
sampling  mill  and  the  concentrator  bins.  The  mill  has  been  used  only 
for  sampling  Southern  Cross  gold  ore,  which  was  not  conveniently 
sampled  in  any  other  way. 

The  crushing  of  the  ore  is  done  entirely  by  jaw  crushers.  The 
cutters  are  of  special  design;  they  have  a wing  much  like  the  Vezin 
wing,  but  oscillate  back  and  forth  in  a horizontal  plane  by  means  of 
a gear-and-crank  mechanism. 

The  Southern  Cross  mill  is  sprinklered  for  fire  protection;  it  is 
cleaned  with  compressed  air,  as  other  mills.  It  has  its  own  bucking 
room  equipped  much  as  the  larger  Anaconda  mill,  but  with  single  units. 


ANACONDA  BUCKING  ROOM 


65 


FIG.  30. — BUCKING  ROOM  AT  ANACONDA  SAMPLING  MILL. 

The  duplicate  and  orderly  arrangement  of  the  equipment  is  prominent.  The  air-driven  shaking  sieves  are  on  the  bench  at  the 

right,  the  cube  mixers  are  on  the  wall  over  the  bench. 

— Photograph  by  Baker,  A.  C.  M.  Co. 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


Flow  Sheet  of  the  Anaconda 
Sampling  Mill — 

Cars  dump  into  bins  under  “high  line” 

Collecting  car  under  bins  supplies  two  50-ton  mill  hoppers 

Shaking  trays 

Jaw  crushers;  12"x24" 

Conveyors  to  elevators 
Elevated  to  top  of  4th  floor 

No  1 cutter;  Brunton  oscillatory,  ll"xl5"  openings,  24  cuts  per 
minute 

Sample;  20% 

Jaw  crushers;  8"xl8" 

No  2 cutters;  Brunton  oscillatory,  7"xll"  openings,  36  cuts  per 
minute 

Sample;  20% 

Shaking  trays 
No.  1 rolls;  15"x40" 

No.  3 cutter;  Brunton  oscillatory,  5.5"x8"  openings,  44  cuts  per 
minute 

Sample;  20% 

Distributing  boxes 
‘ No.  2 rolls;  14"x26" 

. No.  4 cutters;  Brunton  oscillatory,  3.5"x5"  openings,  76  cuts  per 
minute 

Sample;  20% 

Trolley  bucket  or  wheelbarrow  to  steel  floor 

Brunton  split  shovels 

Sample 

Steam  cabinet  dryers 
Engelbach  grinders 
Stand  cutters;  26-slot 
Sample 

Disk  grinders 
Mechanical  sieves  (air) 

Cube  mixers 
Table  riffles;  16-slot 
Sealed  packets 


SAMPLING  IN  CONCENTRATING  AND  CYANIDING  MILLS 


67 


SAMPLING  IN  MONTANA  CONCENTRATING 
AND  CYANIDING  MILLS 

A great  deal  of  sampling  is  done  as  part  of  the  daily  routine  in  all 
concentrating  and  cyaniding  mills.  In  ore  treatment  plants  condi- 
tions are  decidedly  favorable  for  cheap  and  accurate  work.  The 
greatest  difficulty  is  unquestionably  in  the  sampling  of  mill  heads 
where  hardly  less  than  a full  observance  of  all  the  rules  for  crushing 
and  dividing  can  be  expected  to  supply  precise  data. 

Every  tenth  car  of  ore  for  the  great  Anaconda  17,000-ton  con- 
centrator is  sampled  in  the  Anaconda  sampling  mill  which  has  already 
been  described.  All  the  ore  going  to  the  East  Butte  concentrator  is 
sampled  in  the  East  Butte  sampling  mill,  also  one  of  the  mills  de- 
scribed in  this  paper.  The  Butte  and  Superior  concentrator  feed  is 
hand  sampled  every  half  hour;  50  pounds  are  taken  at  each  interval. 
The  Timber  Butte  concentrator  is  equipped  with  a hand  operated 
device  which  cuts  out  samples  from  the  crushed  feed  as  the  stock 
pours  from  one  conveyor  head  to  another  conveyor.  The  Shannon 
mine  of  the  Barnes  King  Company  is  equipped  with  mechanical  con- 
trivances which  automatically  cut  out  portions  of  the  ore  at  the  tram- 
way loading  station;  the  sample  is  worked  down  to  final  pulp  in  the 
customary  way. 

The  sampling  of  the  different  streams  of  mill  pulp  is  carried  out 
in  different  degrees  by  various  means  in  the  several  mills.  Usually 
hand  samples  are  taken  at  designated  intervals.  Swinging  stream 
samplers  are  built  in  a variety  of  models  and  frequently  used..  A com- 
plete automatic  stream  sampling  system  is  in  use  at  the  Butte  and 
Superior  mill;  an  electrical  timing  and  operating  installation  swings 
samplers  across  a half-dozen  streams  at  exactly  8-minute  intervals. 
Milling  work  inevitably  smooths  out  inequalities  in  the  raw  ore;  the 
material  is  abundantly  crushed;  mixings  and  dispersions  occur 
throughout  the  line  of  pulp  flow.  The  required  precision  of  the 
sampling  operation  is  obtained  with  slight  expense  for  installation, 
upkeep,  or  attendance. 

Mill  products  can  be  sampled  as  pulps  while  the  concentrates  are 
flowing  to  collecting  bins;  they  can  be  pipe-sampled  as  lots  in  bins 
or  in  railroad  cars,  or  they  can  be  hand-sampled  by  shovel  and  cone 
and  quarter  methods. 

As  a rule,  ordinary  mill  sampling,  except  for  the  sampling  of  the 
heads,  is  far  easier  to  accomplish  than  the  sampling  of  lots  of  custom 
ere;  mill  heads  require  practically  the  same  treatment  that  lots  get  in 
the  best  of  custom  samplers. 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


es 


SUMMARY  AND  CONCLUSIONS 


The  principles  involved  in  ore  sampling  have  been  more  or  less 
expressed  by  several  writers,  but  no  thoroughly  adequate  and  mathe- 
matical treatment  has  yet  been  given.  The  present  paper  attempts  tc 
analyze  sampling  methods  with  the  theory  of  probability  and  the 
distribution  of  results  strongly  in  mind,  although  a mathematical 
treatment  is  not  attempted.  A lot  of  ore  is  a very  complex  aggregate, 
and  to  the  sampling  deviations  are  added  those  of  chemical  analysis; 
constants  in  an  equation  of  errors,  or  for  qualifying  Woodbridge’s 
table  of  size-weight  relationship. 

The  equipment  for  ore  sampling  which  is  described  in  these  pages 
is  only  that  equipment  found  in  actual  use  in  Montana  at  the  present 
time;  the  range  of  the  types  is  wide  but  by  no  means  includes  excel- 
lent machines  in  use  elsewhere. 

The  figures  given  in  connection  with  the  descriptions  of  riffle 
mixing  and  pipe  sampling  may  give  a better  insight  into  the  character 
of  those  two  operations. 

Sampling  is  now  carried  on  extensively  in  Montana  in  seven 
sampling  mills  and  in  at  least  five  large  and  important  ore-di'essing 
mills.  It  has  been  attempted  to  outline  the  procedure  used  in  the 
different  sampling  mills,  but  a full  account  of  the  sampling  in  the 
twelve  places  would  require  a much  larger  bulletin  than  this  can 
presume  to  be. 

Although  sampling  of  ores  and  mill  pulps  is  a perfectly  practical 
and  common  operation,  certain  features  are  clearly  open  to  change 
and  improvement.  The  more  obvious  possibilities  group  about  pre- 
cision, cost,  efficiency,  fire  risk,  safety,  welfare,  and  hygiene.  There 
always  lurks  the  suspicion  that,  for  the  work  done,  and  the  end 
attained,  present  plants  are  extravagant  in  elevations,  size  of  buildings, 
and  general  capital  outlay  for  equipment  and  attendance.  Montana 
sampling  mills  rank  high  in  most  of  their  technical  features,  with 
certain  attentions  toward  improvement  in  conditions  of  safety,  welfare, 
and  hygiene  they  would  probably  become  the  most  advanced  types  in 
their  field  of  technology. 

The  excellent  results  obtained  by  the  State  Bureau  on  the  different 
samplings  of  the  50-ton  lot  of  ore  demonstrate  the  precision  of  the 
mills  and  the  satisfaction  and  usefulness  of  mechanical  sampling. 


IMPORTANT  PUBLICATIONS  ON  SAMPLING 


69 


■IMPORTANT  PUBLICATIONS  ON  SAMPLING 

1884 — Brunton,  D.  W.  “A  New  System  of  Ore-Sampling.”  Trans. 
Am.  Inst.  Min.  Engrs.,  Vol  13,  p.  639. 

Brunton’s  first  vibratory  cutter  is  described. 

1895 — Brunton,  D.  W.  “The  Theory  and  Practice  of  Ore-Sampling.” 
Trans.  Am.  Inst.  Min.  Engrs.,  Vol.  25,  p.  826. 

An  extended  study  of  the  influence  of  large  particles  and 
rich  minerals  on  the  precision  of  sampling.  Demonstrates 
the  necessity  for  crushing  between  successive  divisions. 

1898 — Hofman,  H.  O.  “The  Metallurgy  of  Lead.”  Hill  Publishing  Co., 
New  York,  5th  Ed.,  9th  Imp. 

Chapter  5 is  a lengthy  discussion  of  hand  and  mechanical 
ore  sampling. 

1902 — Johnson,  Paul.  “An  Automatic  System  of  Sampling.”  Eng.  & 
Min.  J„  Vol.  73,  p.  514. 

Describes  mill  at  Greenwood,  B.  C.,  with  cuts  and  results. 

1908 — Argali,  Philip.  “Machine  Sampling.”  Eng.  & Min.  J.,  Vol. 
86,  p.  291. 

Refutes  statement  that  retardation  causes  error  in  sampling. 

1908 —  Woodbridge,  T.  R.  “Sampling  by  Machine.”  Eng.  & Min.  J., 
Vol.  86,  p.  917. 

Discusses  mechanical  sampling  with  data. 

1909 —  Bailey,  E.  G.  “Accuracy  in  Sampling  Coal.”  J.  Ind.  Eng.  Chem., 
Vol.  I.,  p.  161. 

Discusses  probability  curves  involving  large  errors. 

1909 — Richards,  Robert  H.  “Ore  Dressing.”  McGraw-Hill  Book  Co., 
New  York.  Vol.  III.,  pps.  1570-1578. 

Principles  and  practice  of  sampling  are  discussed. 

1909 — Brunton,  D.  W.  “Modern  Practice  of  Ore-Sampling.”  Trans. 
Am.  Inst.  Min.  Engrs.,  Vol.  40,  p.  567. 

The  Taylor  and  Brunton  system  is  explained.  Brunton’s 
oscillatory  cutter  is  described. 

1909 —  Woodbridge,  T.  R.  “Sampling  by  Machine.”  Eng.  & Min.  J., 
Vol.  87,  p.  269. 

Discusses  mechanical  sampling  with  data. 

1910 —  Weld,  Fred  C.  “Accuracy  in  Sampling.”  J.  Ind.  Eng.  Chem., 
Vol.  2,  p.  426. 

Discusses  application  of  probability  curves  to  sampling. 

1910 — Huntoon,  Louis  D.  “Accuracy  of  Mechanical  and  Riffle  Ore 
Samplers.”  Eng.  & Min.  J.,  Vol.  90,  p.  62. 

Gives  screen  analyses  and  assays  after  riffle  dividing. 


70 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


1916 — Woodbridge,  T.  R.  “Ore  Sampling  Conditions  in  the  West.” 
U.  S.  Bureau  of  Mines,  Technical  Paper  86. 

An  excellent  study  of  the  more  important  aspects  of  hand 
and  mechanical  sampling.  A general  summary  of  western 
practice  is  given  as  well  as  flow  sheets  of  the  mills. 

1919 — Rice,  Claude  T.  “Sampling  Practice  at  Independence  Mill.” 
Eng.  & Min.  J.,  Vol.  107,  p.  641. 

Describes  the  Coard  mixer  and  divider  for  final  pulps. 


A. 


INDEX 


Abraded  iron  

Acknowledgments 
Anaconda — 

bucking  room  ... 

flow  sheet  

sampling-  mills  . 
Analyses — 

Bureau  test  lot 

flotation  car  

lead  bullion  

mixing  test  

Authorization  


Page 
.12,  24 
7 

64 

66 

.60,  61,  62,  63,  64 

42 

31 

11 

15 

7 


B. 


Page 

Equipment  for  sampling 24 

Essential  operations  of  sampling 9 

F. 


Fabrics  for  mixing 13 

Fieldner  on  abraded  iron 24 

Fine  grinding  24,  49 

Fines  in  crushing 11 

Flotation  sampling  10,  29,  31,  67 

Flow  Sheets- — 

Anaconda  66 

East  Butte  45 

East  Helena  44 

Washoe  43 


Brunton — 


on  large  pieces 22 

oscillatory  cutter 


32,  33 

, 34, 

43,  46, 

64 

vibratory  cutter  

..31,  32, 

57 

Bucking  rooms — - 

Anaconda  

64 

East  Butte  

60 

East  Helena  

57 

Washoe  

49 

Bureau  test  lot 

.40  ,41, 

42 

C. 

Cabinet  dryers  

17, 

40 

Cloths  for  rolling 

13 

Concentrating  mills  in  ’ 

Montana 

66 

Conclusions 

68 

Cone  and  quartering.  .. 

.17,  18, 

19 

Cost  of  sampling 

8 

Crosses  for  sampling... 

19, 

56 

Crushers  

24 

Crushing — 

economical  

21 

machinery  

11, 

24 

operation  

9, 

11 

surfaces  

12, 

24 

Cube  mixers  

13, 

64 

Cutters — 

Brunton  31,  32. 

, 33, 

34,  43, 

66 

East  Butte  

34, 

39 

riffle  

13 

Snyder  

36, 

37 

Yezin  

...34, 

36,  51, 

55 

Cutting  

9, 

12,  14, 

15 

G. 


Grab  sampling  flotation  car 31 

Grinder  for  prospectors 23 

Grinding  (see  crushing)  — 

coarse  gold  49 

substance  12,  24 

“Gun’’  sampler  29 

H. 

Hand  shovel  sampling 26 

High  value  minerals 23 

I. 

Impartial  sampling  12 

Influences  in  sampling 19 

Iron — 

in  mixing  test 15 

in  samples  24 

J. 

Jones  riffle  26 

L, 

Large  pieces  11,  12,  21,  22 

Law  of  averages  19,  22 

Lead  sampling  10 

Literature  on  sampling 69,  70 


M. 


D. 


Definition  of  sampling 9 

Dividing — 

lots  9,  12,  19 

instruments  26 

Drum  mixers  33,  39 

Dryers  17,  40 

Drying  samples  9,  17,  40 


E. 

East  Butte — 

cutter  

flow  sheet  

mixers  

sampling  mill  

East  Helena — 

flow  sheet  

rfiffles  

sampling  mills 


34,  35 

45 

38 

.57,  58 


44 

26 


.49,  51,  53 


Mechanical  sampling 

speed  

cheapness  

Methods  of  sampling 
Mills,  sampling — 

Anaconda  

East  Butte  

East  Helena  

Washoe  

Minerals,  high  value.. 
Mixing — 

by  ringing  

drums  

necessity  

samples  

test  

Moisture  sample  

Montana — 

concentrating  mills 
reserve  sample  law 
sampling  mills  .... 


12 

12 

12 

10 

60,  61,  62,  63,  64 

57,  58,  59,  60 

49,51 

43,  46,  47,  48,  49 

23 


19 

36,  38 

9,  13 

.9,  12,  13,  15,  38 

15 

17 


67 

49 

46 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


72 

INDEX — Continued 


N. 

Page 

Number  of  cuts..lO,  12,  15,  19,  21,  26 


0. 

Object  of  bulletin 7 

Operations  of  sampling 9,  21 


P. 


Permissible  weights  23 

Pipe  sampling  11,  29,  30 

Precision  in  sampling 

8,  12,  17,  19,  21,  31,  42 

Principles  of  sampling 9,  19 

Probability — 

curve  21,  22 

sampling  12,  13,  19 

Pulp  mixing  13 

Purpose  of  sampling 8 


R. 


Reserve  samples  

.49, 

57 

Results — 

of  sampling  lead. 

11 

on  test  lot 

42 

Retarding  drums  .... 

.36, 

38 

Riffles  

.12, 

13, 

17, 

27, 

28 

Ringing  the  cone 

19 

Rolling  samples  

13 

S, 

Sample — 

cloths  

13 

division  

.12, 

26 

drying  

- 9, 

17 

mixing  

.12, 

13 

Weights  

23 

Sampler — 

Anaconda  

.12, 

34 

Brunton  

.31, 

32, 

33, 

34 

East  Butte 34, 

45, 

57, 

58, 

59, 

60 

East  Helena  

.49, 

51, 

53, 

54, 

57 

Snyder  

.36, 

37 

Vezin  

.34, 

35, 

51, 

55 

Washoe  

46 

Sampling — 

accuracy  of  

8 

at  Anaconda  

67 

at  Barnes  King 

67 

at  Butte  and  Superior 

67 

at  East  Butte 

67 

at  Timber  Butte.... 

67 

cost  

8 

cone  and  quarter.. 

17 

crosses  

19 

defined  

9 

equipment  

24 

for  moisture  

17 

impartial  

12 

in  West  

10 

influences  

19 

mills  in  Montana.. 

46 

Page 

mixing  9,  12,  13,  15,  17,  38 

molten  lead  10 

necessity  9 

operations  9 

pipe  11,  29 

precision  8,  12 

principles  9 

probability  12,  19 

publications  69,  70 

purpose  8 

sequence  in  10 

test  lot  40 

time  8 

School  of  Mines — 

riffle  13,  26 

Snyder  disk  36 

Segregation  . 13,  19 

Selecting  sample  9,  12 

Sequence  in  sampling 10 

Sieves  43,  44,  45,  49 

Snyder  sampler  . 36,  37 

Southern  Cross  mill 64 

Split  shovels  .25,  26 

Spotty  ores  23 

State  Bureau — 

authorization  _.  7 

staff  4 

test  lot  40,  41 

Summary  68 


T. 


Table  riffles  13 

Taylor  and  Brunton  System  46,  47 

Test — 

of  mixing  15,  17 

of  uniformity  17 

of  sampling ...8,  9,  29,  31,  40,  41 

Theory  of  probability 19 

Time  of  sampling.. 8,  41 


U. 


Uniformity  test  17 

V. 

Yezin  sample  cutters 34,  35,  51,  55 

mixing  drum  38 


W. 


Washoe  sampler — 

bucking  room  49 

description  46 

flow  sheet  ...  43 

Weights  of  sample ...23,  36 

Weld  on  sampling 22 

Western  sampling 10,  21 

W oodbridge — 

on  large  pieces 22 

principles  of  sampling 9 

table  of  safe  weights 23 


PLATE  III. — ELK  BASIN. 

View  from  the  south  rim  looking  northward  into  Montana.  The  conspicuous  escarp- 
ment has  been  produced  by  erosion  along  the  crest  of  the  anticline. 


UNIVERSITY  OF  MONTANA  BULLETIN 

BUREAU  OF  MINES  AND  METALLURGY  SERIES  NO.  4 


GEOLOGY  AND  OIL 
AND  GAS  PROSPECTS 
OF  CENTRAL  AND  EASTERN 
MONTANA 


C.  H.  CLAPP 
ARTHUR  BEVAN 
G.  S.  LAMBERT 


• uC  uu 


OF  ? Hi 


JNIVERSi]  / OF  ILLiNOIS 

STATE  SCHOOL  OF  MINES 
BUTTE,  MONTANA 


STATE  BUREAU  OF  MINES  AND 
METALLURGY 


CLAPP,  CHARLES  H. Director  and  Geologist 

PhD.,  Massachusetts  Institute  of  Technology,  1919 

ADAMI,  ARTHUR  E. Mining  Engineer 

E.  M.  Montana  State  School  of  Mines,  1907 
LAMBERT,  GERALD  S.  - - - - - - Assistant  Geologist 

B.  S.  School  of  Mines  and  Engineering,  Univ.  of  Utah,  1919 

BEVAN,  ARTHUR  C. Assistant  Geologist 

B.  S.  Ohio  Wesleyan  University,  1912. 


PUBLICATIONS 

No.  1.  The  Montana  State  Bureau  of  Mines  and  Metallurgy  (an  ex- 
planation of  its  purpose  and  operation). 

No.  2.  Directory  of  Montana  Metal  and  Coal  Mines. 

No.  3.  Mechanical  Ore  Sampling  in  Montana  (by  H.  B.  Pulsifer). 

No.  4.  Geology  and  Oil  and  Gas  Prospects  of  Central  and  Eastern 
Montana  (with  a geologic  map).  (By  C.  H.  Clapp,  Arthur 
Bevan  and  G.  S.  Lambert.) 


<J-LCsY 


CONTENTS. 


y 

Y 


**  n & • 


PART  I.  By  C.  H.  CLAPP. 

Introduction  

Region  and  field  work 

Authorship  and  acknowledgments 

Bibliography  

Surface  features  

General  geology  


Page. 
...  8 
...  8 
...  9 

...  10 
..  16 
..  18 


PART  II. 


Stratigraphy — 

Cretaceous  and  Tertiary(?)  continental  formations.  By  C.  H. 

Clapp  

Port  Union  formation  

Lance  formation  


hk 


L 

< 

K 

L 


Mesozoic  and  Paleozoic  systems.  By  Arthur  Bevan 

The  Mesozoic  

Cretaceous  system  

Montana  group  

Bearpaw  shale  

Judith  River  formation 

Claggett  formation  

Eagle  and  Yirgelle  sandstones 

Two  Medicine  formation  

Livingston  formation  

Colorado  formation  

Comanchean  system  

Kootenai  formation  

Morrison  formation  

Jurassic  system  

Ellis  formation  

Triassic  system  

Chugwater  formation  

Correlation  of  the  Mesozoic 


25 

26 
29 

34 

36 

37 

38 
41 
46 
49 
52 
33 
54 
57 
57 
60 


62 


62 

65 

65 

65 


Page. 

The  Paleozoic  67 

Carboniferous  system  67 

Quadrant  formation  67 

Madison  limestone  68 

Older  formations  69 

PART  III.  By  G.  S.  LAMBERT. 

Economic  geology  70 

Coal  70 

Oil  and  gas  72 

Development  72 

Production  . 77 

Theoretical  considerations  77 

Possibilities  of  oil  and  gas 84 


ILLUSTRATIONS. 


Plate  I,  Geologic  map  . . In  pocket 

II,  Major  geologic  structures In  pocket 

III,  Elk  Basin  „. Frontispiece 

IV,  Lance  formation  30 

V,  Judith  River  formation  42 

VI,  Eagle  sandstone  48 

VII,  Ellis  formation  . 63 

VIII,  West  Mosby  dome  : 75 


IX  Geologic  structures  favorable  to  oil  and  gas  accumulation....  81 


PART  I 

BY 

C.  H.  CLAPP 

INTRODUCTION 
Region  and  Field  Work. 

On  account  of  the  discovery  of  oil  in  central  Montana,  and  the 
consequent  interest  in  the  oil  resources  of  the  state,  the  State  Bureau 
of  Mines  and  Metallurgy  undertook  a geological  survey  of  the  oil  and 
gas  possibilities  of  Montana.  Because  of  the  greatly  deformed  and 
fractured  character  of  the  rocks  in  the  western,  mountainous  region, 
it  was  believed  that  only  in  the  central  and  eastern  portions  of  the 
state  are  oil  and  gas  possibilities  of  immediate  prospective  value. 
Hence,  during  the  first  season,  only  that  porton  of  the  state  east 
of  the  main  front  range  of  mountains  was  surveyed.  However,  as 
that  portion  constitutes  nearly  two-hirds  of  the  entire  state,  98,000  • 
square  miles  out  of  a total  of  147,000  square  miles,  a task  of  consid- 
erable magnitude  for  a single  season  was  undertaken. 

A base  map  on  a scale  of  four  miles  to  an  inch  was  compiled 
and  on  this  was  assembled  all  of  the  available  geological  information 
from  reliable  sources,  chiefly  the  publications  of  the  United  States 
Geological  Survey.  In  this  way,  several  areas,  approximating  50,000  i 
square  miles  in  extent,  were  mapped  with  varying  degrees  of  accuracy,  | 
leaving  several  large  unmapped  areas.  Thus  there  remained  to  be  ) 
mapped  during  the  season  of  1920  about  48,000  square  miles  of  terri- 
tory, distributed  throughout  central  and  eastern  Montana. 

Two  parties  were  organized,  one  consisting  of  G.  S.  Lambert  and 
Arthur  Bevan,  and  the  other  of  C.  H.  Clapp  and  R.  J.  Wade.  Mr. 
Bevan  left  for  the  field  on  June  14,  accompanied  by  C.  W.  Vaupell, 
who  assisted  him  until  July  1,  when  G.  S.  Lambert  joined  the  party. 
Lambert  and  Bevan  finished  their  field  work  on  September  22.  C. 

H.  Clapp  left  for  the  field  on  July  9 and  returned  on  August  28. 
Since  then  a 3-day  trip  was  made  to  the  Cat  Creek  oil  field  by  Clapp 
and  Lambert  during  the  last  part  of  December.  There  were  only  152 
party  days  spent  on  actual  field  work,  which  necessitated  an  average 
of  315  square  miles  of  mapping  per  party  day. 

The  mapping,  therefore,  was  obviously  of  a reconnaissance  nature, 
but  was  checked  by  the  work  of  several  private  surveys,  as  well  as  by 
the  work  of  the  United  States  Geological  Survey  in  areas  not  yet 


FIELD  WORK  AND  ACKNOWLEDGMENTS 


published  by  them.  No  detailed  work  was,  of  course,  possible.  Nearly 
all  the  surveyed  roads  in  the  region  were  traversed  in  automobiles, 
locations  being  made  from  section  corners  and  by  measurement  of 
distances  with  a speedometer.  In  unsurveyed  townships,  compass 
traverses  were  made  of  the  roads,  and  distant  contacts  were  located 
by  a rough  compass  triangulation. 

For  publication  the  accompanying  geologic  map  of  central  and 
eastern  Montana,  on  a scale  of  1:500,000,  or  about  8 miles  to  an  inch, 
has  been  compiled  by  G.  S.  Lambert.  The  base  map  was  compiled  by 
the  United  States  Geological  Survey  in  1913  and  has  been  corrected 
and  brought  up  to  date  by  A.  L.  Longley  with  data  from  the  United 
States  Land  Survey  plats  of  1913  to  1919. 

Authorship  and  Acknowledgments. 

The  table  of  contents  names  the  individual  author  of  each  portion 
of  the  report,  but  all  portions  were  written  after  conference  and  dis- 
cussion of  all  portions  by  all  three  authors.  Much  of  the  report  must 
be  considered  as  a compilation  of  reports  already  published,  dealing 
with  the  geology  and  mineral  resources  of  central  and  eastern  Mon- 
tana. Even  for  those  areas,  a geologic  map  of  which  has  not  been 

heretofore  published,  a large  part  of  the  information  has  been  obtained 
from  others. 

It  is  not  feasible,  even  if  it  were  possible,  to  acknowledge  by 
name  all  of  those  to  whom  credit  is  due  for  both  general  and  specific 
information.  The  United  States  Geological  Survey  has  furnished  by 
far  the  major  part  of  the  data  for  both  the  report  and  map.  Those 
papers  prepared  by  the  staff  of  the  survey,  which  were  actually  used 

during  the  survey  and(  preparation  of  the  report  are  listed  in  the 

bibliography  and  specific  mention  is  made  to  several  of  them  through- 
out the  report.  In  addition,  a map  of  the  central  and  eastern  part  of 
Montana  was  prepared  by  the  United  States  Geological  Survey  showing 
several  important  geologic  boundaries,  especially  in  areas  where  no 
geologic  maps  have  been  published.  These  boundaries  were  not  every- 
where accepted,  but  were  used  where  the  writer’s  own  work  was  too 
general  or  incomplete. 

Acknowledgment  to  the  Geological  Department  of  the  Anaconda 
Copper  Mining  Company  should  also  be  made.  It  was  in  this  depart- 
ment that  both  the  field  and  final  maps  were  compiled  and  draughted. 
Although  all  members  of  the  department  contributed  to  the  accuracy 
and  value  of  the  maps,  specific  acknowledgment  is  made  to  Mr.  A.  L. 
Longley  in  charge  of  the  draughting,  to  Mr.  P.  R.  Murphy,  who  com- 
piled the  geology  for  the  field  maps,  and  to  Messrs.  George  Fowler  and 
Paul  Billingsly,  who  have  been  in  charge  of  much  of  the  areal  geologic 
surveys  and  development  for  oil  and  gas  carried  on  by  the  company. 

Mr.  Eugene  Milburn  of  Miles  City  furnished  the  writer  with  many 
reports  by  various  geologists  obtained  during  his  investigation  of  the 


10 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


oil  and  gas  resources  of  the  state.  Areal  information  has  also  been 
obtained  from  Mr.  Julius  H.  Warner,  of  the  East  Butte  Copper  Com- 
pany. Detailed  information  and  logs  of  wells  have  been  freely  given 
by  most  of  the  oil  operators  and  geologists  of  the  state.  To  many 
others  the  authors  are  indebted  for  the  aid  which  has  been  given  to 
them. 

Bibliography. 

The  following  list  is  not  a complete  bibliography  of  all  the  papers 
relative  to  the  geology  and  mineral  resources  of  central  and  eastern 
Montana.  A complete  bibliography  dealing  with  the  geology  of  the 
state  is  being  compiled  and  will  be  published  later.  In  the  following 
list  an  attempt  has  been  made  to  give  only  the  more  important  and 
latest  papers,  for  where  a later  publication  supersedes  an  earlier  one, 
the  earlier  one  has  not  been  given.  All  papers  used  during  the  work 
have,  of  course,  been  listed.  The  papers  are  first  listed  in  the  order 
of  their  publication  and  then  indexed  according  to  the  counties  to 
which  they  refer. 

(1)  Hayden,  F.  V., 

Geology  of  the  Missouri  Valley:  U.  S.  Geol.  Survey.  Terr. 
Prelim.  (Fourth  Ann.)  Kept.,  1871. 

(2)  Weed,  W.  H., 

The  Laramie  and  the  overlying  Livingston  formation  of 
Montana:  U.  S.  Geol.  Survey  Bull.  105,  1893. 

(3)  Iddings,  J.  P.  and  Weed,  W.  H., 

U.  S.  Geol.  Survey  Geol.  Atlas,  Livingston  folio  (No.  1), 
1894. 

(4)  Weed,  W.  H.  and  Pirsson,  L.  V., 

Geology  and  mineral  resources  of  the  Judith  Mountains  of 
Montana;  U.  S.  Geol.  Survey,  Eighteenth  Ann.  Kept.,  Part 
3,  pp.  437-616,  1898. 

(5)  Weed,  W.  H., 

Geology  of  the  Little  Belt  Mountains,  Montana;  U.  S. 
Geol.  Survey  Twentieth  Ann.  Bept.  Part  3,  1899. 

(6)  Weed,  W.  H., 

U.  S.  Geol.  Survey  Geol.  Atlas,  Fort  Benton  folio  (No.  5), 
1899. 

(7)  Weed,  W.  H., 

U.  S.  Geol.  Survey  Geol.  Atlas,  Little  Belt  Mountains 
folio  (No.  5),  1899. 

(8)  Willis,  Bailey, 

Oil  of  the  northern  Rocky  Mountains:  Eng.  and  Mining 
Jour.,  Vol.  72,  pp.  782-784,  1901. 

(9)  Hatcher,  J.  B., 

Relative  age  of  the  Lance  Creek  beds  of  Converse  County, 
Wyo.,  the  Judith  River  beds  of  Montana,  and  the  Belly 
River  beds  of  Canada:  Am.  Geologist,  Vol.  31,  p.  369, 

1903. 


BIBLIOGRAPHY 


11 


(10)  Stanton,  T.  W.,  and  Hatcher,  J.  B., 

The  stratigraphic  position  of  the  Judith  River  beds  and 
their  correlation  with  the  Belly  River  beds:  Science,  new 
ser.,  vol.  18,  p.  212,  1903. 

(11)  Stanton,  T.  W.,  and  Hatcher,  J.  B., 

Geology  and  palentology  of  the  Judith  River  beds;  U.  S. 
Geol.  Survey  Bull.  257,  1905. 

(12)  Darton,  N.  H., 

Geology  of  the  Bighorn  Mountains:  U.  S.  Geol.  Survey 

Prof.  Paper  51,  1906. 

(13)  Darton,  N.  H., 

Coals  of  Carbon  County,  Montana:  U.  S.  Geol.  Survey 
Bull.  316-C,  pp.  174-193,  1907. 

(14)  Fisher,  C.  A., 

Southern  extension  of  the  Kootenai  and  Montana  coal 
bearing  formations  in  northern  Montana:  Econ.  Geol.,  vol. 
3,  pp.  94-96,  1908. 

(15)  Washburne,  C.  H., 

Coal  fields  of  the  northeast  side  of  the  Bighorn  Basin, 
Wyo.,  and  of  Bridger,  Montana:  U.  S.  Geol.  Survey  Bull. 
341,  1909. 

(16)  Fisher,  C.  A., 

Geology  and  water  resources  of  the  Great  Falls  region, 
Montana:  U.  S.  Geol.  Survey  Water-Supply  Paper  221, 
1909. 

(17)  Leonard,  A.  G.,  and  Smith,  C.  D., 

The  Sentinel  Butte  lignite  field,  North  Dakota  and  Mon- 
tana: U.  S.  Geol.  Survey  Bull.  341-A,  pp.  15-35,  1909. 

(18)  Collier,  A.  J.,  and  Smith,  C.  D., 

The  Miles  City  coal  field,  Montana:  U.  S.  Geol.  Survey 
Bull.  341-A,  pp.  36-61,  1909. 

(19)  Stone,  R.  W., 

Coal  near  the  Crazy  Mountains,  Montana:  U.  S.  Geol. 

Survey  Bull.  341-A,  pp.  78-91,  1909. 

(20)  Woodruff,  E.  G., 

The  Red  Lodge  coal  field,  Montana:  IT.  S.  Geol.  Survey 
Bull.  341-A,  pp.  92-107,  1909. 

(21)  Fisher,  C.  A., 

Geology  of  the  Great  Falls  coal  field,  Montana:  U.  S. 
Geol.  Survey  Bull.  356,  1909. 

(22)  Calvert,  W.  R., 

Geology  of  the  Lewistown  coal  field,  Montana:  U.  S. 
Geol.  Survey  Bull.  390,  1909. 

(23)  Smith,  C.  D., 

The  Fort  Peck  Indian  Reservation  lignite  field,  Montana: 
U.  S.  Geol.  Survey  Bull.  300,  1909. 


12 

(24) 

(25) 

(26) 

(27) 

(28) 

(29) 

(30) 

(31) 

(32) 

(33) 

(34) 

(35) 

(36) 

(37) 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 
Pepperberg,  L.  J., 

The  Milk  River  coal  field,  Montana:  U.  S.  Geol.  Survey- 

Bull.  381-A,  1910. 

Stone,  R.  W.,  and  Calvert,  W.  R., 

Stratigraphic  relations  of  the  Livingston  formation  of 
Montana:  Econ.  Geol.  Vol.  5,  pp.  551-557,  652-669,  741-761, 

1910. 

Peale,  A.  C., 

On  the  stratigraphic  position  and  age  of  the  Judith  River 
formation:  Jour.  Geol.  20,  pp.  350-549,  640-652,  738-757, 

551-7,  652-669,  741-764,  1912. 

Calvert,  W.  R., 

Geology  of  certain  lignite  fields  in  eastern  Montana:  U. 

S.  Geol.  Survey  Bull.  471-D,  pp.  187-201,  1912. 

Bowen,  C.  F., 

The  Baker  lignite  field,  Montana:  U.  S.  Geol.  Survey  Bull. 
471-D,  pp.  202-226,  1912. 

Herald,  F.  A., 

The  Terry  lignite  field,  Montana:  U.  S.  Geol.  Survey 

Bull.  471-D,  pp.  227-270,  1912. 

Hance,  J.  H., 

The  Glendive  lignite  field,  Montana:  U.  S.  Geol.  Survey 

Bull.  471-D,  pp.  271-283,  1912. 

< 

Stebinger,  Eugene, 

The  Sidney  lignite  field,  Montana:  TJ.  S.  Geol.  Survey 

Bull.  471-D,  pp.  284-318,  1912. 

Beekly,  A.  L., 

The  Culbertson  lignite  field,  Montana:  U.  S.  Geol.  Sur- 

vey Bull.  471-D,  pp.  319-358,  1912. 

Pepperberg,  L.  J., 

The  southern  extension  of  the  Milk  River  coal  field, 
Montana:  U.  S.  Geol.  Survey  Bull.  471-E,  pp.  359-383, 

1912. 

Calvert,  W.  R., 

The  Livingston  and  Trail  Creek  coal  fields,  Montana: 

U.  S.  Geol.  Survey  Bull.  471-E,  pp.  384-405,  1912. 

Calvert,  W.  R., 

The  Electric  coal  field,  Montana:  U.  S.  Geol.  Survey  , 

Bull.  471-E,  pp.  406-422,  1912. 

Rogers,  G.  S., 

The  Little  Sheep  Mountain  coal  field,  Montana:  U.  S. 

Geol.  Survey  Bull.  531-F,  pp.  159-227,  1913. 

Bauer,  C.  M., 

Lignite  in  the  vicinity  of  Plentywood  and  Scobey,  Mon- 
tana: U.  S.  Geol.  Survey  Bull.  541-H,  pp.  293-315,  1914. 


BIBLIOGRAPHY 


13 


(38)  Rogers,  G.  S., 

Geology  and  coal  resources  of  the  area  southwest  of  Cus- 
ter, Yellowstone  and  Big  Horn  counties,  Montana:  U.  S. 

Geol.  Survey  Bull.  541-H,  pp.  316-328,  1914. 

(39)  Bowen,  C.  F., 

Coal  discovered  in  a reconnaissance  survey  between  Mus- 
selshell and  Judith,  Montana:  U.  S.  Geol.  Survey  Bull. 

541-H,  pp.  329-337,  1914. 

(40)  Bowen,  C.  F., 

The  Cleveland  coal  field,  Montana:  U.  S.  Geol.  Survey 

Bull.  541-H,  pp.  338-355,  1914. 

(41)  Bowen,  C.  F., 

The  Big  Sandy  coal  field,  Montana:  U.  S.  Geol.  Survey 
Bull.  541-H,  pp.  356-378,  1914. 

(42)  Huntley,  L.  G., 

Oil,  gas,  and  water  content  of  Dakota  sand  in  Canada 
and  the  United  States:  Am.  Inst.  Min.  Eng.  Bull.  102, 
pp.  1333-1353,  1915. 

(43)  Rowe,  Jesse  Perry, 

Probable  oil  and  gas  in  Montana:  Eng.  and  Min.  Jour., 
vol.  99,  pp.  647-649,  1915. 

(44)  Bowen,  C.  F., 

Possibilities  of  oil  in  the  Porcupine  dome,  Montana:  U. 

S.  Geol.  Survey  Bull.  621-F,  pp.  61-70,  1916. 

(45)  Stebinger,  Eugene, 

Geology  and  coal  resources  of  northern  Teton  County, 
Montana:  U.  S.  Geol.  Survey  Bull.  621-K,  pp.  117-156, 

1916. 

(46)  Rowe,  J.  P.  and  Wilson,  R.  A., 

Geology  and  economic  deposits  of  a portion  of  eastern 
Montana:  Univ.  of  Montana  (State  University)  Studies, 

No.  1,  1916. 

(47)  Bard,  D.  C.,  and  Steele,  Chester, 

Present  status  of  oil  and  gas  prospecting  in  Montana: 
Quarterly  Journal  of  the  Montana  Soc.  of  Engineers,  vol. 
1,  No.  3,  pp.  329,  1916. 

(48)  Stebinger,  Eugene, 

Possibilities  of  oil  and  gas  in  north  central  Montana: 
U.  S.  Geol.  Survey  Bull.  641-C,  pp.  49-91,  1917. 

(49)  Calvert,  W.  R., 

Geology  of  the  Upper  Stillwater  Basin,  Montana:  U.  S. 
Geol.  Survey  Bull.  641-G,  1917. 

(50)  Barnett,  Y.  H., 

Geology  of  the  Hound  Creek  district  of  the  Great  Falls 
coal  field,  Montana:  U.  S.  Geol.  Survey  Bull.  641-H,  pp. 

215-231,  1917. 


14  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

(51)  Stebinger,  Eugene, 

Anticlines  in  the  Blackfeet  Indian  Reservation,  Montana: 
U.  S.  Geol.  Survey  Bull.  641-J,  pp.  281-305,  1917. 

(52)  Richards,  R.  W.,  Lupton,  C.  T.,  and  Woolsey,  L.  H., 

The  Bull  Mountain  coal  field,  Montana:  U.  S.  Geol. 

Survey  Bull.  647,  1917. 

(53)  Collier,  A.  J., 

The  Bowdoin  dome,  Montana;  a possible  reservoir  of  oil 
or  gas;  U.  S.  Geol.  Survey  Bull.  661-E,  pp.  193-209,  1917. 

(54)  Hancock,  E.  T., 

• Geology  and  oil  and  gas  prospects  of  the  Lake  Basin 
Field,  Montana:  U.  S.  Geol.  Survey  Bull.  691-D,  pp.  101- 

148,  1918. 

(56)  Stebinger,  Eugene, 

Oil  and  gas  geology  of  the  Birch  Creek-Sun  River  area, 
northwestern  Montana:  U.  S.  Geol.  Survey  Bull.  691-E, 

pp.  149-184,  1918. 

(56)  Bowen,  C.  F-., 

Anticlines  in  a part  of  the  Musselshell  Valley,  Montana: 
U.  S.  Geol.  Survey  Bull.  691-F,  pp.  185-210,  1919. 

(57)  Hancock,  E.  T., 

Geology  and  oil  and  gas  prospects  of  the  Huntley  field, 
Montana:  U.  S.  Geol.  Survey  Bull.  711-G,  1920. 

(58)  Thom,  W.  T., 

An  Upper  Cretaceous  seacoast  in  Montana:  John  Hopkins 
Univ.  Circ.  new  ser.,  No.  3,  pp.  68-73,  March,  1917. 

(59)  Collier,  A.  J., 

Geology  of  northeastern  Montana:  U.  S.  Geol.  Survey 

Prof.  Paper  120-B,  pp.  17-39,  1918. 

(60)  Condit,  D.  D., 

Relations  of  late  Paleozoic  and  early  Mesozoic  formations 
of  southwestern  Montana  and  adjacent  parts  of  Wyoming: 
U.  S.  Geol.  Survey  Prof.  Paper  120,  pp.  111-121,  1918. 

(61)  Bowen,  C.  F., 

Gradation  from  continental  to  marine  conditions  of  depo- 
sition in  central  Montana  during  the  Eagle  and  Judith 
River  epochs;  U.  S.  Geol.  Survey  Prof.  Paper  125-B,  pp. 
11-21,  1919. 

(62)  Cross,  Whitman, 

Are  the  Lance  and  Fort  Union  formations  of  Mesozoic 
time?  Science,  p.  305,  April  1,  1921. 

(63)  Schuchert,  Charles, 

Are  the  Lance  and  Fort  Union  formations  of  Mesozoic 
time?  Science,  pp.  45-47,  Jan.  14,  1921. 

(64)  Knowlton,  F.  H., 

Are  the  Lance  and  Fort  Union  formations  of  Mesozoic 
time?  Science,  p.  307,  April  1,  1921. 


BIBLIOGRAPHY 


15 


County- 


Big'  Horn 

Blaine 

Carbon 

Carter 

Cascade 

Chouteau 

Custer 

Dawson 

Fallon 

Fergus 

Flathead 

Gallatin 

Garfield 

Glacier 

Hill 

Lewis  & Clark 

Liberty 

McCone 

Madison 

Meagher 

Musselshell 

Park 

Phillips 

Pondera 

Powder  River 

Prairie 

Richland 

Roosevelt 

Rosebud 

Sheridan 

Stillwater 

Sweetgrass 

Teton 

Toole 

Valley 

Wheatland 

Wibaux 

Yellowstone 

General  Stratigraphy 

Other  General  Papers 


(Numbers  refer  to  the  foregoing  bibliographic 
list) 


(12)  (38)  (57)  (60) 

(24)  (33)  (40)  (48)  (59) 

(13)  (15)  (20)  (49)  (60) 

(5)  (6)  (7)  (16)  (21)  (48)  (50) 

(6)  (41)  (48) 

(18)  (27)  (28)  (29)  (36) 

(27)  (30)  (31) 

(27)  (28)  (29) 

(4)  (6)  (7)  (16)  (21)  (22)  (39)  (48)  (61) 

(8) 

(3)  (7)  (34)  (60) 

(59)  (61) 

(45)  (48)  (51) 

(24)  (33)  (48) 

(55) 

(45)  (48) 

(23)  (59) 

(60) 

(5)  (7)  (19)  (56) 

(39)  (52)  (54)  (56) 

(3)  (7)  (34)  (35)  (60) 

(48)  (53)  (59) 

(45)  (48)  (51)  (55) 

(27)  (29)  (36) 

(23)  (27)  (31)  (59) 

(23)  (32)  (59) 

(36)  (44)  (61) 

(32)  (37)  (59) 

(3)  (49)  (54)  (60) 

(3)  (7)  (34)  (54)  (56)  (60) 

(48)  (55) 

(45)  (48)  (51) 

(23)  (53)  (59) 

(7)  (19)  (52) 

(17)  (27)  (29)  (30)  (31) 

(38)  (54)  (57)  (60) 

(1)  (2)  (9)  (10)  (11)  (14)  (25)  (26)  (58) 

(62)  (63)  (64) 

(42)  (43)  (46)  (47) 


16 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


SURFACE  FEATURES. 

The  eastern  part  of  Montana  is  in  the  Great  Plains  region  of 
North  America,  and  the  western  part  lies  within  the  Rocky  Mountain 
system  of  the  mountainous  Cordellera  of  the  continent.  Thus  the 
state  is  divided  into  a western  mountainous  district  and  an  eastern 
plains  or  prairie  district,  constituting  almost  two-thirds  of  the  state. 
Although  the  boundary  between  the  two  districts  is  fairly  well  defined, 
crossing  the  state  with  a general  N.  35°  W.  trend,  the  western  part 
of  the  prairie  district  is  characterized  by  several  small  ranges  or 
groups  of  mountains,  rising  island-like  above  the  general  prairie  level 
for  over  200  miles  east  of  the  main  mountain  front.  The  prairie  region 
itself  may,  therefore,  be  subdivided  into  a western  and  an  eastern 
part,  Central  Montana  and  Eastern  Montana.  Thus  the  surface  feat- 
ures of  Montana  divide  the  state  into  three  distinct  geographic  dis- 
tricts, Western,  Central  and  Eastern  Montana.  This  report  deals  exclu- 
sively with  Central  and  Eastern  Montana. 

In  Central  Montana  the  rocks  are  conspicuously  folded  with  a 
general  northwest  trend,  whereas  in  Eastern  Montana,  except  in  two 
or  three  places,  the  rocks  are  nearly  flat  lying  or  dip  at  angles  of 
less  than  five  degrees.  Hence  in  Central  Montana  the  more  resistant 
rocks  form  the  ranges  and  groups  of  mountains,  which  rise  island-like 
above  the  general  level  of  the  prairies  by  2000  to  6000  feet,  whereas 
in  Eastern  Montana  there  are  no  distinct  groups  of  mountains,  although 
in  places  high  cuestas,  mesas,  and  buttes  surmount  the  general  prairie 
level  by  1000  to  2000  feet. 

Central  and  Eastern  Montana  are  drained  by  prevailingly  eastward 
and  northeastward  flowing,  consequent  streams,  and  owing  to  the  semi- 
arid  climate  by  only  relatively  few  tributaries  of  an  insequent  nature. 
In  Central  Montana,  however,  some  of  the  tributary  streams  follow 
soft  rock  belts  and  hence  are  subsequent  streams.  With  the  exception 
of  St.  Mary  River,  which  rises  in  the  mountains  a few  miles  south  of 
the  Canadian  border  and  enters  the  Saskatchewan,  all  the  rivers 
drain  into  the  Missouri,  which,  rising  in  the  mountains,  flows  gener- 
ally eastward  across  the  prairie.  Its  main  tributary,  the  Yellowstone, 
rises  in  the  mountains  of  northwestern  Wyoming  and  flows  northeast, 
joining  the  Missouri  in  North  Dakota  just  east  of  the  Montana  line. 
These  two  rivers  divide  Central  and  Eastern  Montana  into  three  nearly 
equal  portions  extending  east  from  the  mountains  to  the  North  Dakota 
boundary. 

North  of  the  Missouri,  following  for  some  distance  the  pre- 
Glacial  channel  of  the  Missouri,  is  the  Milk  River.  Between  the 
Missouri  and  the  Yellowstone  is  the  Musselshell.  South  of  the  Yellow- 
stone are  several  large  streams,  flowing  into  it,  which,  enumerated  from 
west  to  east,  are  the  Big  Horn,  Rosebud,  Tongue,  and  Powder  rivers, 
all  except  the  Rosebud  having  their  source  in  Wyoming.  The  extreme 


SURFACE  FEATURES 


17 


southeastern  part  of  the  state  is  crossed  by  Little  Missouri  River, 
which  enters  the  Missouri  in  North  Dakota. 

The  outlying  ranges  and  groups  of  mountains  of  Central  Mon- 
tana consist  from  north  to  south  of  the  Sweetgrass  Hills,  near  the 
Canadian  border;  the  Bearpaw  and  Little  Rocky  mountains,  between 
the  Milk  and  Missouri  rivers;  the  Little  Belt,  Highwood,  Moccasin, 
and  Judith  mountains  south  of  the  Missouri;  the  Castle  and  Big 
Snowy  mountains,  north  of  the  Musselshell;  the  Crazy  mountains  be- 
tween the  Musselshell  and  Yellowstone  rivers;  and  the  Pryor  and  Big- 
horn mountains  south  of  the  Yellowstone.  The  Pryor  mountains,  lying 
wholly  within  Montana,  are  the  northwestern  portion  of  the  Bighorn 
Mountains  uplift,  which  was  completely  bisected  by  the  Bighorn  River. 

Most  of  the  mountains  enumerated  above  are  relatively  low,  in 
groups  wThich  are  10  to  40  miles  across,  each  of  which  consists  of  a 
maturely  eroded  dome,  exposing  in  most  groups  a central  core  of 
resistant  igneous  rocks.  Only  the  higher  peaks  of  the  Little  Belts, 
Big  Snowy,  Crazy,  and  Bighorn  mountains  have  been  glaciated  into 
saw-tooth  or  serrated  summits,  whereas  the  other  peaks,  although 
usually  steep  and  rugged,  have  more  or  less  rounded  or  nearly  level 
summits.  The  highest  summits  occur  in  the  Crazy  Mountains  which, 
although  carved  from  nearly  flat  sediments  intruded  by  resistant 
igneous  rocks,  are  over  11,000  feet  above  sea  level,  or  6000  feet  above 
the  surrounding  plains. 

Eastern  Montana  consists  of  a broad,  nearly  level  or  gently  sloping 
plain,  above  which  remnants  of  former  plains  and  slopes  still  remain 
to  form  mesas,  buttes,  and  cuestas.  Cut  into  the  plain  are  the  youth- 
ful to  mature  valleys  of  the  present  streams,  which,  in  some  places, 
have  developed  broad  flood  plains,  and,  in  other  places,  still  flow  in 
narrow,  although  not  very  deep,,  gorges.  In  most  places  the  insequent 
tributary  streams  of  the  larger  rivers,  throughout  a zone  varying  in 
width  from  less  than  a mile  to  over  10  miles,  have  cut  the  prairie 
plain  into  breaks  or  bad  lands. 

The  prairie  plains  slope  in  general  toward  the  north  and  north- 
east, so  that  the  elevation  of  the  dominant  rolling  prairie  plain  ranges 
from  4000  feet  above  sea-level  in  Central  Montana  to  2300  feet  in  the 
extreme  northeastern  part  of  the  state.  Into  this  plain  the  larger 
rivers  have  cut  their  valleys  to  a depth  of  100  to  500  feet.  The 
lowest  elevation  in  the  state  occurs  where  the  Missouri  and  the  Yel- 
lowstone cross  the  North  Dakota  boundary,  each  at  an  elevation  of 
somewhat  less  than  1900  feet  above  sea-level. 

Few  of  the  buttes,  mesas,  or  cuestas  surmount  the  prairie  level  by 
more  than  500  to  1000  feet.  The  principal  mesas  are  the  gravel  cov- 
ered plateaus  along  the  Canadian  border(l);  Larb  Hills  between  the 


(1)  Described  by  A.  J.  Collier,  Geology  of  northeastern  Montana;  U.  S.  Geol. 
Survey,  Prof..  Paper  120-B,  page  19,  1918. 


18 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


Milk  and  Missouri  rivers;  the  Piney  and  Black  buttes  north  of  the 
Missouri;  the  Sheep  and  Little  Sheep  mountains  north  of  the  Yellow- 
stone; Bull  Mountains  between  the  Musselshell  and  Yellowstone  rivers; 
Pine  Ridge  between  the  Yellowstone  and  Bighorn  rivers;  and  a num- 
ber of  conspicuous  white  buttes  in  the  southeastern  part  of  the  state. 

The  Wolf  and  Rosebud  mountains  are  the  highest  and  most  exten- 
sive of  the  mesas.  Taken  as  a whole  they  form  a broad  synclinal 
plateau  between  Little  Bighorn  River  and  the  deeply  eroded  northern 
part  of  the  Black  Hills  uplift  in  the  southeastern  corner  of  the  state. 
The  western  portion  of  the  plateau,  to  which  the  name  of  Wolf  Moun- 
tains is  applied,  forms  a westward  facing  cuesta,  whose  steep  front 
slope  is  from  1500  to  2000  feet  high,  the  maximum  elevation  of  the 
cuesta  being  5663  feet  above  sea-level.  The  rocks,  and  hence  the  sur- 
face of  the  cuesta,  dip  gently  eastward  to  elevations  of  less  than 
4000  feet.  The  eastern  portion  of  the  plateau,  known  as  Piniele  Ridge, 
forms  a far  less  conspicuous  eastward  facing  cuesta  surmounting  the 
lowland  plain  cut  in  the  non-resistant  rocks  of  the  Black  Hills  uplift. 
The  plateau  is  deeply  cut  by  the  Rosebud,  Tongue,  and  Powder  rivers, 
and  near  its  northern  edge  is  dissected  into  a number  of  small  mesas 
and  buttes  surmountaing  the  prevailing  lowland  level,  which  merges 
toward  the  north  and  east  into  the  rolling  prairie  characteristic  of  the 
greater  part  of  Eastern  Montana.  ! 

North  of  the  Yellowstone  in  the  vicinity  of  Forsyth,  is  a dome 
shaped  uplift  40  by  30  miles,  the  limbs  of  which  dip  at  angles  up  to  40 , 
degrees.  Where  the  more  resistant  rocks  dip  more  steeply  than  10 « 
degrees,  conspicuous  ridges  are  formed.  Similar  ridges  occur  along  the 
steeply  dipping  southwestern  limb  of  the  Cedar  Creek  anticline,  extend- 
ing from  Glendive  on  the  Yellowstone  S.  30°  E.  into  North  Dakota. 
Less  conspicuous  and  smaller  ridges  or  cuestas  surround  the  Black  j 
Hills  uplift  in  the  extreme  southeastern  portion  of  the  state. 

In  a few  placees,  in  and  near  the  dome  northwest  of  Forsyth  and  j 
west  of  Jordan  between  the  Piney  and  Black  buttes,  are  resistant* 
dikes  of  igneous  rocks  which  form  small  ranges.  Smoky  Buttes;  west  f 
of  Jordan,  is  the  most  conspicuous,  surmounting  the  prairie  level  by  « 
400  feet. 

GENERAL  GEOLOGY. 

The  sedimentary  rocks  of  Eastern  Montana  are  almost  everywhere 
flat  lying  or  gently  dipping.  The  older  sedimentary  rocks  of  Central 
Montana  have,  however,  been  deformed  and  intruded  by  igneous  rocks, 
while  the  sedimentary  rocks  of  Western  Montana  are  still  older  and 
more  deformed  and  have  been  intruded  by  larger  and  more  frequent 
bodies  of  igneous  rocks.  The  base  of  the  main  front  range  of  the 
Rocky  Mountain  system  roughly  marks  the  boundary  between  the 
less  deformed  rocks  of  Eastern  and  Central  Montana  and  the  greatly 
deformed  and  igneous  rocks  of  the  western  part  of  the  state,  and  has 


GENERAL  GEOLOGY 


19 


been  taken  as  the  western  boundary  of  the  area  mapped  and  described 
in  this  report. 

Although  the  sedimentary  and  metamorphic  rocks  of  Montana  range 
in  age  from  the  most  ancient,  Archeau,  to  the  most  modern,  Quatern- 
ary and  Recent,  those  of  Central  Montana  are  dominantly  of  middle 
age,  late  Paleozoic  and  Mesozoic,  and  those  of  Eastern  Montana  are 
dominantly  early  modern,  late  Mesozoic  and  presumably  early  Cenozoic. 
A large  part  of  Central  and  Eastern  Montana  is  covered  by  a mantle 
of  loosely  consolidated  or  unconsolidated  drift,  which  north  of  the 
Missouri  river  consists  chiefly  of  glacial  detritus.  Elsewhere  the  drift 
consists  of  gravels,  sands,  and  muds  deposited  in  the  streams  and  lakes 
which  have  drained  the  mountains  to  the  west,  from  the  time  of  the 
mountainous  uplift  in  the  early  Cenozoic.  Of  these  mantle  rocks, 
however,  only  the  Recent  alluvium  deposits  in  the  valleys  of  the  larger 
rivers  have  been  mapped. 

The  oldest  rocks  shown  on  the  accompanying  map,  the  Madison 
limestone,  and  rocks  of  the  Quadrant  formation,  are  of  late  Paleozoic, 
Mississippian  and  Pennsylvanian,  ages.  They  are  exposed  only  around 
the  flanks  of  the  mountain  uplifts  of  Central  Montana.  Overlying 
them,  and  structurally  speaking,  virtually  conformable  with  them, 
although  angular  unconformities  do  occur,  are  the  rocks  of  Mesozoic 
and  early  Cenozoic(?)  (Fort  Union)  ages,  several  thousand  feet  in 
thickness.  In  spite  of  their  great  thickness  and  the  great  length  of 
time  during  which  they  were  deposited,  no  significant  angular  uncon- 
formities, indicating  widespread  deformation  and  prolonged  erosion 
occur.  There  are,  however,  certain  horizontal  unconformities  or  dis- 
conformities,  indicating  time  intervals  during  which  there  was  little 
or  no  deposition,  but  doubtless  some  local  erosion. 

However,  resting  upon  the  older  rocks,  with  marked  angular  un- 
conformity, and  exposed  only  in  the  southeastern  part  of  the  state,  are 
sedimentary  rocks  of  early  Cenozoic  (Oligocene)  age,  known  as  the 
White  River  beds.  Thus  it  appears  as  if  the  only  marked  period  of 
deformation  and  igneous  intrusion  that  has  affected  the  Mesozoic  and 
Fort  Union  rocks  of  Montana,  occurred  after  the  deposition  of  the 
Fort  Union  and  previous  to  the  deposition  of  the  White  River  beds. 
The  exact  age  of  the  Fort  Union  is  doubtful.  It  has  been  generally 
considered  to  be  of  earliest  Cenozoic,  Eocene,  age,  and  has  been  so 
considered  in  this  report  and  on  the  accompanying  map.  But  as  dis- 
cussed later  it  is  perhaps  better  considered  to  be  of  latest  Mesozoic, 
that  is,  latest  Cretaceous  age,  in  which  case  the  period  of  deformation 
must  have  occurred  during  the  Epi-Mesozoic  (Mesozoic-Cenozoic)  inter- 
val or  during  the  Eocene  epoch. 

During  the  deformation  the  rocks  of  Central  Montana  were  flexed 
into  open  folds  with  a general  northwest  trend,  the  actual  bearing  of 
the  axes  of  the  major  folds  varying  from  N.  15°  W.  to  nearly  due 
East  and  West.  Although  the  limbs  of  some  of  the  major  folds  were 
steeply  tilted  to  angles  of  25  to  50  degrees  from  the  horizontal,  in 


20  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

most  of  the  folds  east  of  the  main  front  range  the  limbs  were  not  i 
more  steeply  tilted  than  5 to  10  degrees. 

In  Eastern  Montana  the  rocks  were  only  slightly  tilted  toward  the 
northeast,  or  were  gently  uplifted  to  form  large,  isolated  anticlines. 
With  one  exception,  a relatively  narrow  anticline  in  the  extreme  east- 
ern part  of  the  state,  the  anticlines  are  dome  shaped  uplifts  10  to  50 
miles  across,  from  which  the  component  rocks  dip  away  in  all  direc- 
tions. The  crest  of  the  dome  in  the  southeastern  corner  of  the  state 
occurs  in  Wyoming,  so  that  in  Montana  the  rocks  dip  only  to  the 
northeast,  north,  and  northwest. 

The  major  axis  of  folding  in  Central  Montana  extends  along  the 
crest  of  the  Bighorn  Mountains  uplift,  through  a region  characterized 
by  several  small  folds,  to  the  Little  Belt  Mountains  uplift;  and  thence 
north  along  the  crest  of  a broad,  northward  plunging,  uplift,  called  the 
Sweetgrass  arch,  to  the  Canadion  border.  The  general  trend  of  the 
axis  is  N.  33°  W.  but  in  detail  it  varies  from  N.  15°  to  75°  W. 

The  Bighorn  Mountains  uplift  in  Montana  consists  of  a north- 
westerly plunging  anticline  30  miles  across,  striking  N.  50°  W.  Al- 
though in  places  the  limbs  of  the  anticline  dip  at  angles  of  more  than 
45°,  in  most  places  they  dip  at  angles  of  less  than  20°.  Furthermore, 
the  rocks  flatten  out  rapidly  away  from  the  uplift  and  the  limbs 
of  the  major  fold,  except  as  described  below,  are  fairly  regular  and' 
free  from  faults,  although  there  are  several  places  where  the  limbs 
flatten  out  to  form  noses  or  terraces,  and  along  the  flanks  there  are, 
a few  closed  anticlines  and  domes. 

Along  Yellowstone  River,  in  the  vicinity  of  Billings,  25  miles 
north  of  the  Pryor  Mountains,  the  younger  rocks  have  been  affected  by 
the  Bighorn  Mountains  uplift  and  have  been  deformed  into  a number 
of  minor  folds  broken  by  numerous  faults. (2)  The  most  remarkable 
feature  of  the  structure  is  a long  narrow  belt  of  faulting  82  miles  long,; 
but  not  more  than  6 miles  wide,  extending  from  Township  4 North,. 
Range  17  East,  to  Township  1 North,  Range  31  East.  The  belt  trends' 
N.  80°  W.  but  the  faults  almost  universally  strike  to  the  northeast, ‘I 
N.  50°  E.  being  the  average  strike.  Hancock(3)  suggests  torsional; 
movements  as  a probable  cause  of  the  localized  faulting  along  the 
narrow  belt,  the  torsional  stresses  resulting  from  the  Big  Horn  uplift  to 
the  south  and  the  group  of  small  uplifts  and  Little  Belt  Mountain 
uplift  to  the  northwest. 

North  of  the  belt  of  faulting  and  southeast  of  the  Little  Belt 
Mountains  uplift  there  are,  as  has  already  been  mentioned,  several 
relatively  small  folds  whose  axes,  like  the  faults  just  described,  have 
a general  easterly  or  northeasterly  trend.  Of  these  the  major  folds  are 
the  Big  Coulee-Hailstone  dome,  the  Shawmut  anticline,  and  the  Elk 

(2)  For  detailed  description  of  the  structure  see  Hancock,  E.  T.,  Geology  and 
Oil  and  Gas  Prospects  of  the  Huntley  Field,  Montana  ; U.  S.  Geol.  Survey  Bull. 
711-G,  pages  139-140,  1920;  and  Geology  and  Oil  and  Gas  Prospects  of  the  Lake 
Basin  Field,  Montana,  U.  S.  Geol.  Survey  Bull.  691-D,  pages  131-141,  1918. 

(3)  Idem. 


STRUCTURAL  FEATURES 


21 


uplift.  The  three  major  structures  may  themselves  be  divided  into 
minor  anticlines,  domes,  and  terraces,  forming  on  the  east  and  north- 
east flanks  of  the  Big  Coulee-Hailstone  dome,  the  Broadview  dome  and 
Belmont  terrace,  and  on  the  southwest  flank  the  Gibson  dome;  at 
the  west  end  of  the  Shawmut  anticline  the  West,  Middle  and  East 
Domes;  and  in  the  Elk  uplift,  the  Big  Elk,  Little  Elk,  Haymaker,  and 
Daisy  Dean  domes. 

The  Little  Belt  Mountains  uplift  is  a large  anticline,  85  miles 
long,  and  50  miles  across,  striking  N.  75°  W.  It  plunges  in  all  direc- 
tions except  toward  the  west  and  southwest,  in  which  directions  it 
merges  into  the  still  larger  anticline  that  forms  the  Big  Belt  Moun- 
tains, one  of  the  front  ranges  of  the  Rocky  Mountains.  The  limbs 
of  the  Little  Belt  Mountains  anticline  are  flexed  into  several  liiinor 
folds  and  are  broken  by  faults.  Most  of  the  minor  folds  plunge  away 
from  the  major  uplift  to  form  a series  of  radial  crests.  Some  of 
them,  however,  are  completely  enclosed  to  form  domes  such  as  the 
Skull  Butte  and  Stockett  domes. 

The  Sweetgrass  arch,  north  of  the  Little  Belt  Mountains  uplift, 
is  a broad,  flat  topped  anticline,  130  miles  long,  and  80  miles  wide. 
It  strikes  3ST.  15°  W.  and  plunges  to  the  northwest.  The  limbs  of  the 
folds  dip  at  very  low  angles  and  are  flexed  into  but  few  minor  anti- 
clines or  terraces.  There  may  be  local  anticlines  and  domes  within  the 
arch,  but  this  can  be  determined  only  by  detailed  field  work. 

Between  the  major  axis  of  anticlinal  folding  just  described  and 
the  axis  of  much  greater  deformation  along  the  main  front  range  of 
the  Rocky  Mountain  system,  is  a synclinal  area  15  to  75  miles  wide. 
It  is,  however,  interrupted  in  its  central  portion  by  an  anticline,  which 
extends  east  from  the  Big  Belt  Mountains  anticline  through  the  Little 
Belt  Mountains  and  Big  Snowy  Mountains  anticlines  into  eastern  Mon- 
tana. Within  the  synclinal  area  are  numerous,  relatively  small  anti- 
clines and  domes.  Those  south  of  the  Little  Belt  Mountains  anticline 
are  Potter  Basin  dome,  McLeod  dome,  Dean  anticline,  Dry  Creek  dome, 
and,  with  only  their  northern  parts  within  Montana,  Elk  Basin  and 
Frannie  domes.  North  of  the  Little  Belt  Mountains  the  synclinal  area 
may  be  divided,  as  described  by  Stebinger(4),  into  two  structural 
areas,  an  eastern  area  in  which  the  beds  are  nearly  horizontal  or  very 
gently  folded,  and  a western  area  in  which  the  beds  have  been  greatly 
folded  and  broken  by  faulting.  In  the  eastern  area  the  rocks  dip 
gently  westward  at  an  average  angle  of  20°  to  30°,  but  there  are 
several  terraces  and  anticlines,  of  which  the  larger  and  better  en- 
closed are  the  Willow  Creek  anticline,  Dupuyer  anticline,  Scoffin 
Butte  anticline,  the  anticlines  on  Birch  Creek,  the  Blacktail  Creek  anti- 
cline, the  Cut  Bank  Creek  anticline  and  one  3 miles  to  the  southwest, 

(4)  Stebinger,  Eugene,  Geology  and  coal  resources  of  northern  Teton  Conuty, 
Montana;  U S.  Geol.  Survey  Bull.  621-K  pp.  128-129,  1916;  Anticlines  in  the 
Biackfeet  Indian  Reservation,  Montana;  U.  S.  Geol.  Survey  Bull.  641- J.,  pp.  292-294, 
1917;  and  Oil  and  gas  geology  of  the  Birch  Creek-Sun  River  Area,  Northwestern 
Montana,  J.  S.  Geol.  Survey  Bull.  691-E.,  pp.  168-182,  1919. 


22 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


and  an  anticline  on  the  North  Fork  of  Milk  River.  In  the  western 
area  the  folds  are  all  long  and  narrow  and  many  are  broken  by  strike 
faults,  but  there  are  several  enclosed  anticlines  which  are  structurally 
favorable  to  the  accumulation  of  oil  and  gas.  These  are  noted  and 
named  on  the  accompanying  geologic  and  structural  maps. 

The  huge  east-west  anticline,  which,  as  described  above,  interrupts 
the  synclinal  area  east  of  the  main  front  range,  has  a general  N.  81°  W. 
trend,  although  the  western  portion  strikes  more  nearly  east  and  west 
than  the  eastern  portion.  The  anticline  is  characterized  by  several 
minor  anticlines  and  domes,  and  hence  is  properly  called  an  anti- 
clinorium.  East  of  the  Little  Belt  Mountains  anticline,  which  has 
already  been  described,  there  is  a well  defined  anticline  along  the 
north  and  along  the  south  edge  of  the  anticlinorium,  the  two  anticlines 
being  separated  by  a broad,  nearly  flat,  synclinal  area.  The  outer 
limbs  of  the  two  anticlines  dip  steeply  away  from  the  major  axis  at 
angles  ranging  from  5°  to  85°,  averaging  in  the  western  portion  40° 
to  50°  and  in  the  eastern  portion  5°  to  10°,  whereas  the  inner  limbs 
dip  gently  toward  the  central  synclinal  area  at  angles  averaging  less 
than  5°. 

Just  east  of  the  Little  Belt  Mountains  the  two  anticlines  consist 
of  the  Big  Snowy  Mountains  uplift  on  the  south  and  a number  of 
much  smaller  uplifts  forming  the  Judith  and  Moccasin  mountains  on 
the  north.  The  latter  are  to  a great  extent  laccolithic  uplifts(5) 
and  it  is  probable  that  the  former  is  of  the  same  nature,  although, 
as  yet,  no  extensive  core  of  igneous  rocks  has  been  exposed  by  erosion 
in  the  Big  Snowy  Mountains.  The  asymetrical  character  of  the  south- 
ern anticline  is  well  developed  in  the  Big  Snowy  Mountains  uplift,  but 
not  in  the  Judith  and  Moccasin  Mountains  uplifts.  Furthermore,  the 
central  synclinal  area  between  the  two  major  uplifts  is  distinguished 
by  several  smaller  domes  which  also  appear  to  be  laccolithic  in 
origin(6). 

Farther  east  the  two  anticlines  are  known  as  the  Cat  Creek 
anticline  on  the  north  and  the  Devil’s  Basin  anticline  on  the  south. 
The  two  anticlines  pitch  in  general  to  the  southeast  away  from  the 
Judith  and  Big  Snowy  Mountains  uplifts,  but  are  characterized  by 
several  domes,  forming  completely  enclosed  structures.  Along  the  Cat 
, Creek  anticline  there  are  from  west  to  east  the  Black  Butte,  Kootenai, 
Brush  Creek,  Oiltana,  West  Mosby,  and  East  Mosby  domes.  Along 
the  Devil’s  Basin  anticline  there  are  from  west  to  east  the  Devil’s 
Basin,  Big  Wall,  Howard  Coulee  and  Ragged  Point  domes. 

Between  the  Cat  Creek  and  Devil’s  Basin  anticlines  the  synclinal 
area  is  warped  into  broad  open  folds,  the  largest  of  which  consists  of 
the  Button  Butte  terrace  and  the  Flat  Willow  anticline. 


(5)  Weed,  W.  H.,  and  Pirsson,  L.  V.,  Geology  and  mineral  resources  of  the  Ju- 
dith Mountains  of  Montana ; U.  S.  Geol.  Survey,  Eighteenth  Ann.  Rept.  Part  3,  pp. 
437-616,  1898. 

(6)  Calvert,  W.  R.,  Geology  of  the  Lewistown  coal  field,  Montana;  U.  S.  Geol. 
Survey  Bull.  390,  pp.  48-51,  1909. 


STRUCTURAL  FEATURES 


23 


East  of  Musselshell  River  the  two  anticlines  are  less  well 
developed  and  both  culminate  and  terminate  in  a single  huge  dome, 
40  by  30  miles,  called  the  Porcupine  dome.  The  anticlines  do  continue, 
however,  and  the  northern  is  represented  by  the  McGinnis  Creek 
dome  in  township  13  North,  Range  34  East,  and  a terrace  on  the  north 
flank  of  the  Porcupine  dome  in  townships  13  and  14  North,  Ranges 
37  and  38  East;  and  the  southern  is  represented  by  the  Sumatra  anti- 
cline, Ingomar  dome,  and  a terrace  on  the  south  flank  of  the  Porcu- 
pine dome  in  Townships  6 and  7 North,  Ranges  37  and  38  East. 
The  only  rocks  younger  than  the  definitely  known  Cretaceous  (Colo- 
rado and  Montana)  in  the  entire  anticlinorium  form  a synclinal  area 
of  Lance  sandstones  between  the  Sumatra  anticline  and  the  McGinnis 
Creek  dome. 

Between  the  Devil’s  Basin  anticline  and  the  Big  Coulee-Hailstone 
dome  and  Shawmut  anticline  are  two  anticlines.  The  northeastern, 
which  plunges  to  the  southeast,  is  divided  into  two  parts  called  the 
Devil’s  Pocket  and  Pole  Creek  anticlines,  and  the  southern,  which  is 
completely  enclosed  with  relatively  steep  dips  on  the  northeast  and 
southwest,  is  called  the  Woman’s  Pocket  anticline. 

North  of  the  low  east-west  anticlinorium  is  another  less  well 
developed  anticlinorium  striking  N.  60°  W.  Along  its  axis  are  three 
groups  of  dome  shaped  uplifts,  presumably  laccolithic  in  character. 
These  form,  from  northwest  to  southeast,  the  Sweetgrass  Hills  and 
Bearpaw  and  Little  Rocky  mountains.  All  of  them  have  a central 
core  of  igneous  rocks,  although  those  in  the  Bearpaw  Mountains  are 
largely  of  volcanic  origin. 

Between  the  Moccasin  and  Judith  mountains  on  the  south  and  the 
Bearpaw  Mountains  on  the  north  and  also  to  the  north  of  the  Bear- 
paw Mountains  are  several  small  anticlinal  or  monoclinai  structures 
most  of  them  faulted. (7)  The  better  known  of  these  are  the  struc- 

tures in  the  vicinity  of  Winifred,  south  of  the  Bearpaw  mountains, 
and  the  Havre,  Brown’s  Coulee,  Red  Rock  Coulee,  Lodge  Creek, 
Battle  Creek,  Coal  Creek,  and  Signal  Butte  anticlines  north  of  the 
Bearpaw  Mountains. 

With  one  exception  the  Cedar  Creek  anticline,  the  major  uplifts 
of  Eastern  Montana  are  dome  shaped.  In  the  northern  part  of  the 
state  is  the  Bowdoin  dome (8)  over  60  miles  in  diameter  but  with  very 
low  dips,  usually  less  than  1°.  On  the  southeast  flank  of  the  Bowdoin 
dome,  completely  enclosed  but  virtually  a terrace,  is  the  Poplar  dome, 
20  miles  in  diameter.  Between  the  two  domes  are  at  least  two  an- 
clines.  The  one  best  developed  extends  through  Wolf  Point  with  a 
general  N.  20°  W.  trend,  with  limbs  which  have  a maximum  dip  of 
4°.  To  the  north  of  the  Poplar  dome  are  three  low  anticlinal  areas 


(7)  Stebinger,  Eugene,  Oil  and  gas  in  north-central  Montana  U.  S.  Geol.  Sur- 
vey Bull,  641-C,  pp.  65-88,  1917. 

(8)  Collier,  A.  J.,  The  Bowdoin  dome,  Montana;.  U.  S.  Geol.  Survey  Bull. 
661-E,  pp.  205-207,  1917. 


24 


MONTANA  STATE  BU 1EAU  OF  MINES  AND  METALLURGY 


forming  the  Coal  Creek  dome,  Scobey  anticline,  and  Big  Muddy  Creek 
dome. 

In  the  central  part  of  Eastern  Montana  is  the  Porcupine  dome  al- 
ready described  and  the  long  relatively  narrow  anticline,  known 
either  as  the  Cedar  Creek  or  Glendive-Baker  anticline,  which  extends 
from  north  of  the  Yellowstone  Biver,  west  of  Glendive,  S.  30°  E.  into 
North  Dakota.  The  west  limb  of  the  anticline  is  much  steeper  than 
the  east  limb,  having  an  average  dip  of  about  20°  whereas,  the  aver- 
age dip  of  the  east  limb  is  less  than  5°.  West  of  Baker  the  west 
limb  is  complicated  by  minor  folds,  the  axes  of  which  are  parallel  to 
the  major  fold. 

In  the  southeastern  corner  of  the  state  are  two  dome  shaped 
uplifts  with  a broad  terrace  to  the  west.  The  uplifts  represent  the 
northern  extension  of  the  major  Black  Hills  uplift  into  Montana. 
Between  the  two  uplifts  is  a shallow  synclinal  area  which  is  compli- 
cated by  both  minor  parallel  and  cross  folds.  The  southern  and  larger 
of  the  two  uplifts  is  also  complicated  by  both  parallel  and  cross 
minor  folding  to  form  in  places  enclosed  anticlines  such  as  the  Seven 
Mile  and  Five  Mile  domes. 


PART  II 


CRETACEOUS  AND  TERTIARY  CON- 
TINENTAL FORMATIONS 

BY 

C.  H.  CLAPP 

The  rocks  which  overlie  the  definitely  known  Cretaceous  rock  of 
the  Montana  group  have  been  mapped  as  belonging  either  to  the  Lance 
or  to  the  Fort  Union  formations.  In  general  they  have  been  formed 
under  very  different  conditions  from  the  underlying  rocks  which  are 
largely  marine  and  are  continuous  and  fairly  uniform  over  large  areas. 
The  rocks  of  the  Lance  and  Fort  Union  formation  are  almost 
entirely  of  fresh  water  or  continental  origin,  and  vary  greatly  in  detail 
within  relatively  limited  areas;  although  their  general  characteristics  are 
persistent  through  the  greater  part  of  Central  and  Eastern  Montana. 
The  age  of  these  two  formations  has  been  the  subject  of  a great  deal  of 
controversy,  which  lately  has  broken  out  with  renewed  vigor.  It  is 
out  of  place  to  discuss  the  subject  in  detail  in  a report  of  this  kind, 
especially  as  the  authors  have  not  given  the  matter  detailed  study. 

The  United  States  Geological  Survey  after  a consideration  of  all 
available  evidence-,  (9)  most  of  which  has  been  secured  by  its  own 
investigators,  considers  the  Lance  formation  to  be  of  doubtful  lower- 
most Tertiary  age  and  the  Fort  Union  to  be  definitely  of  Tertiary, 
Eocene  age.  Some  of  the  Survey  geologists,  (10)  for  several  reasons, 
such  as  the  recently  discovered  occurrence  of  a marine  member,  the 
Cannonball,  in  the  upper  part  of  the  Lance  in  southwestern  North 
Dakota,  which  carries  a fauna  much  more  closely  connected  with 
the  Cretaceous  than  with  the  Eocene,  believe  that  the  Lance  is 
Cretaceous.  Schuchert(ll)  has  gone  further  and  considers  both  the 
Lance'  and  Fort  Union  as  Cretaceous,  basing  his  conclusion  largely 
on  the  essential  continuity  of  the  Fox  Hills,  Lance,  and  Fort  Union. 
With  this  premise  the  present  author  is  in  complete  agreement.  Even 
Knowlton(12)  one  of  the  strongest  advocates  of  the  theory  that  the 


(9)  Cross,  Whitman,  Science,  April  1,  1921,  page  305. 

(10)  The  latest  paper  is  by  Stanton,  T.  W.,  The  Fauna  of  the  Clannon-ball 
marine  member  o fthe  Lance  formation  U.  S.  Geol.  Survey  Prof,  paper  128-A,  1920. 

(11)  Schuchert,  Charles,  Are  the  Lance  and  Fort  Union  formations  of  Meso- 
zoic Time?  Science,  pp.  45-47,  Jan.  14,  1921. 

(12)  Knowlton,  F.  H.,  Science,  April  1,  1921,  page  307. 


26 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


Lance  and  Fort  Union  formations  are  of  Tertiary  age,  states  that,  “If 
the  Cannonball  marine  member  of  the  Lance  formation  is  Cretaceous, 
then  both  Lance  and  Fort  Union  are  Cretaceous,  for  there  is  no  stop- 
ping short  of  the  top  of  the  Fort  Union.  ” If  diastrophism  is  to  be 
the  basis  of  periods  or  systems,  certainly  Schuchert  *s  conclusion  is 
sound,  for,  from  the  extensive  reconnaissance  carried  on  in  Montana, 
there  is  no  question  that  there  is  no  essential  break,  sudden  change, 
or  marked  deformation  following  the  close  of  the  deposition  of  the 
Bearpaw  shale  until  after  the  deposition  of  the  Fort  Union  formation. 

The  late  Cretaceous  sandstanes  of  Fox  Hills  age,  variously  mapped 
in  Montana  as  Lennep,  Colgate,  and  Horsethief  sandstones  so  closely 
resemble  the  overlying  true  Lance,  it  was  impossible  by  rapid  rcon- 
naissance  to  distinguish  between  them  on  lithologic  or  structural 
grounds.  There  is  no  important  or  widespread  erosion  interval,  and  in 
many  places  there  is  no  essential  lithologic  difference  between  the 
sandstones  which,  at  the  top  of  the  Bearpaw,  are  found  interbedded 
with  it  in  a transitional  zone  30  to  60  feet  thick,  and  the  normal 
sandstones  of  the  unquestioned  Lance.  Therefore,  for  the  purpose  of 
the  reconnaissance  mapping  all  the  sandstones  and  clays  largely  of 
fresh  water  origin  directly  overlying  tne  Bearpaw  Shale  were  mapped 
as  Lance,  and  have  been  considered  as  of  Cretaceous  age.  The  lower 
limit  of  the  Lance  has  been  placed  at  the  base  of  the  first  thick  and 
persistent  sandstone  overlying  the 'Bearpaw  shale. 

The  upper  limit  of  the  Lance  has  been  determined  partly  by  the 
difference  in  color  between  the  Lance  and  overlying  Fort  Union;  the 
Lance  in  general  being  dull  and  somber,  whereas,  the  Fort  Union 
shows  bright,  contrasting  colors.  The  limit  has  been  determined  large- 
ly, however,  by  the  occurrence,  either  of  the  Lebo  shale,  the  basal 
member  of  the  Fort  Union,  or  of  the  lowest  persistent  coal  or  lignite 
seam.  In  this  report,  following  the  practice  of  the  United  States  Geo- 
logical Survey,  the  Fort  Union  has  been  considered  as  of  Tertiary, 
Eocene,  age. 

Fort  Union  formation. — The  Fort  Union  formation  was  named  in 
1862  by  Meek  and  Hayden(13)  from  a former  military  post  on  the 
Missouri  River  in  North  Dakota,  about  3 miles  from  the  Montana 
boundary,  where  the  formation  is  typically  exposed.  For  several  years 
the  rocks  of  the  Fort  Union  and  Lance  formations  were  referred  to 
the  Laramie,  but  since  1907,  when  detailed  work  in  the  lignite  and 
coal  areas  of  Montana  and  North  Dakota  was  begun  by  the  United 
States  Geological  Survey,  the  rocks  have  been  definitely  subdivided 
into  the  Lance  and  Fort  Union  formations. 

The  Fort  Union  directly  underlies  the  greater  part  of  Eastern 


(13)  Meek,  F.  B.,  and  Hayden,  F.  W.,  Description  of  new  lower  Silurian  (Prim- 
ordial), Jurassic,  Cretaceous,  and  Teritary  fossils  collected  in  Nebraska  by  the 
exploring  expedition  nder  the  command  of  Capt.  W.  F.  Reynolds,  U.  S.  Topog. 
Eng.,  with  some  remarks  on  the  rocks  from  which  they  were  obtained:  Acad.  Nat. 
Sci.  Phila.  Proc.,  vol.  13,  p.  433,  1862. 


FORT  UNION  FORMATION 


2 rt 


Montana  and  is  continuously  exposed  over  an  area  of  nearly  25,000 
square  miles.  It  has  been  largely  eroded  along  the  principal  rivers, 
and  from  the  major  uplifts,  Bowdoin  and  Poplar  domes,  Cedar  Creek 
anticline,  and  the  northern  extension  of  the  Black  Hills  uplift  in  the 
southeastern  part  of  the  state.  The  only  large  area  of  Fort  Union 
rocks  in  Central  Montana,  an  area  of  over  1000  square  miles  in 
extent,  is  that  of  the  Bull  Mountain  coal  field,  an  elliptical  synclinal 
basin,  50  by  30  miles.  Smaller  areas  are  also  found  underlying  Pine 
Ridge,  southeast  of  the  Bull  Mountain  area;  in  the  Red  Lodge  coal 
field  and  in  Crazy  Mountains.  The  former  area  has  been  mapped  as 
Lance  by  Rogers(14),  but  before  the  Lance  and  Fort  Union  beds  were 
separated  as  definitely  as  they  are  today.  Another  small  area  of 
Fort  Union  rocks,  less  than  2 square  miles  in  extent,  has  been  mapped 
by  Bowen(15),  six  miles  east  of  Big  Sandy  in  Chouteau  county.  Its 
presence  in  this  locality,  far  removed  from  all  other  known  areas  of 
Fort  Union  rocks,  is  due  to  faulting,  which  has  brought  the  beds  down 
to  the  level  of  older  rocks.  It  is,  of  course,  possible  that  the  coal 
bearing  rocks  of  the  St.  Mary  River  formation  and  the  overlying 
Willow  Creek  formation  mapped  by  Stebinger(16)  are  in  part  the 
equivalent  of  the  Fort  Union,  but  the  authors  have  preferred  to  map 
them  as  of  Lance  age. 

The  rocks  of  the  Fort  Union  formation  consist  of  coarse  to  fine 
grained,  loosely  to  firmly  cemented  arkosic  (feldspathic  and  mica- 
ceous) sandstones  and  sandy  clays,  and  clay-shales  in  about  equal 
amounts.  JNkimerous  lignite  beds,  which  grade  into  sub-bituminous  coal 
seams  in  Central  Montana,  occur  throughout  the  formation.  As  a rule 
the  sandstones  are  massive,  fairly  thick  bedded,  and  of  a light  yellow 
color,  and  the  clays  are  either  dark  or  greenish  gray,  brownish,  or 
nearly  white,  and  where  clinkered  by  the  burning  of  underlying  lignites 
are  bright  red.  In  general,  therefore,  the  prevailing  appearance  of 
the  Fort  Union  is  in  marked  contrast  to  the  more  uniform,  dull  and 
somber  appearing  rocks  of  the  Lance.  In  places,  however,  the  litho- 
logic distinction  is  not  clear,  the  prevailing  color  of  the  Fort  Union 
rocks  being  ash  gray (17). 

Concretions  of  spherical  to  cylindrical,  log-like  shapes  are  common, 
especially  in  the  lower  part  of  the  formation.  The  concretions  consist 
of  more  firmly  cemented  sandstone  in  the  loosely  cemented  sandstones, 
and  of  calcareous  and  sideritie  (iron  carbonate)  replacements  in  the 
shales.  In  a few  places (18)  in  the  sandstones  are  lenses  of  conglom- 


(14)  Rogers,  G.  Sherbune,  Geology  and  coal  resources  of  area  southwest  of  Cus- 
ter, Montana:  Bull.  541-H,  pp.  30-31,  1914. 

(15)  Bowen,  C.  F„  Big  Sandy  coal  field,  Montana:  U.  S'.  Geol.  Survey,  Bull. 
541-H,  pp.  74-75,  1914. 

(16)  Stebinger,  Eugene,  Geology  and  Coal  Resources  of  northern  Teton  County, 
Montana:  U.  S.  Geol.  Survey,  Bull.  621-K,  pp.  124-128,  1916. 

j17)  Stebinger,  Eugene,  Sidney  lignite  field,  Montana:  U.  S.  Geol.  Survey,  Bull 
4/1,  p.  Zo5,  1912. 

(18)  Woolsey,  L.  H.,  and  others,  Bull  Mountain  coal  field,  Montana;  U.  S.  Geol. 
Survey  Bull.  647,  pp.  27,  1917,  and  Rogers,  G.  S.,  Little  Sheep  Mountain  Coal 
field,  Montana:  U.  S.  Geol.  Survey,  Bull.  531-F.,  p.  11,  1913. 


28 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


erate,  consisting  of  shale  and  sandstone  pebbles  in  a sandstone  matrix. 
Many  of  the  sandstones  are  locally  laminated  and  cross  stratified  as 
a result  apparently  of  depositions  both  from  water  and  from  wind. 
In  the  shales,  many  of  which  are  calcareous,  there  are  in  places,  many 
flakes  and  small  crystals  of  gypsum,  so  that  the  weathered  surface 
resembles  in  places  the  outcrop  of  the  Bearpaw  shales.  In  the  Bull 
Mountain  area  there  are  also  thiri  layers,  1 to  3 feet  thick,  of  buff 
limestone(19). 

The  Fort  Union  formation  is  in  most  places  readily  subdivided  into 
a lower  part  consisting  largely  of  clav-shale,  sandy  shale,  and  soft 
sandstone,  which  has  been  called  the  Lebo  shale  member(20)  and  an 
upper  part  consisting  chiefly  of  sandstones  more  massive  and  resistant 
than  any  of  those  found  in  the  Lebo  shale  member.  Over  a large 
area  in  Central  and  the  western  portion  of  Eastern  Montana,  the  Lebo 
shale  contains  a considerable  amount  of  tuffaceous  andesitic  material, 
and  it  is  on  the  basis  of  this  and  of  stratigraphic  position  also(21) 
that  correlation  is  made  with  the  “Lebo  shale  andesitic  member  of 
the  Fort  Union/’  at  the  type  locality  northeast  of  Crazy  Mountains. 

In  the  extreme  eastern  part  of  the  state  there  is  little  distinction 
in  the  lithology  of  the  lower  and  upper  parts  of  the  Fort  Union.  Coal 
and  lignite  seams  are  found  in  both  the  Lebo  shale  and  overlying  sand- 
stones, but  few  of  the  seams  in  the  Lebo  shale  proper  are  of  the  best 
quality  and  in  many  places  are  merely  carbonaceous  shales (22). 

The  Fort  Union  rocks,  at  least  south  of  the  area  covered  by  glacial 
drift,  are  well  exposed.  Where  flat  lying  or  nearly  so,  the  sandstones 
form  buttes,  mesas,  and  terraces,  terminated  by  scarps,  50  to  100 
feet  high.  In  places  the  sandstones  weather  into  smooth  rounded 
faces,  but  more  commonly  into  fantastic  forms  and  pinnacles  with 
honey-combed  surfaces.  The  shales  weather  into  gentler  and  smoother 
slopes  and  rounded  buttes,  and  in  favorable  places  into  badland  topog- 
raphy. Where  more  steeply  dipping,  the  sandstones  form  ridges  or 
cuestas,  between  valleys  cut  in  the  less  resistant  shale. 

Although  local  unconformities  occur  in  most  places,  the  Lance 
formation  and  the  Lebo  shale  appear  to  be  generally  conformable  and 
to  represent  virtually  continuous  deposition.  The  same  is  true  of 
the  contact  of  the  Lebo  shale  with  the  overlying  and  much  thicker 
part  of  the  Fort  Union  formation,  and  therefore,  although  erosion  has 
removed  hundreds  of  feet  from  the  top  of  the  Fort  Union,  no  signifi- 
cant amount  of  erosion  has  occurred  during  its  accumulation.  The 
Lebo  shale  is  estimated  to  be  from  200  to  300  feet  thick,  but  as  men- 
tioned, thins  out  to  nothing  in  the  eastern  part  of  the  state.  The 


(19)  Woolsey,  L.  H.  and  others,  Bull  Mountain  coal  field,  Montana;  U.  S. 
Geol.  Survey,  Bull.  647,  p.  28,  1917. 

(20)  Stone,  R.  W.,  and  Calvert,  W.  R.,  Stratigraphic  relations  of  the  Livingston 
formation  of  Montana:  Econ.  Geology,  vol.  5,  p.  746,  1910. 

(21)  Rogers,  G.  S.,  Little  Sheep  Mountain  coal  field,  Montana:  U.  S.  Geol.  Sur- 
vey, Bull.  531-F.,  p.  15,  1913. 

(22)  Hancock,  E.  T.,  Geology  and  oil  and  gas  prospects  of  the  Huntley  field, 
Montana:  U.  S.  Geol.  Survey,  Bull.  711-G,  pp.  126-127,  1920. 


LANCE  FORMATION 


29 


Fort  Union  is  variously  estimated  throughout  Eastern  Montana  from 
1000  to  1400  feet  thick,  but  to  the  west  it  thickens.  In  the  Bull 
Mountain  area,  where  presumably  the  amount  of  erosion  is  greater 
than  in  Eastern  Montana,  the  upper  part  of  the  formation  alone  is 
1650  feet  thick,  and  although  the  Lance  and  Fort  Union  formations 
do  not  appear  to  have  been  definitely  separated  in  the  Bed  Lodge  and 
Crazy  Mountains  areas,  yet  the  undoubted  Fort  Union  rocks  are  at  least 
2800  feet  in  the  former(23)  and  over  3000  feet  in  the  latter  area(24). 

Detailed  sections  of  the  Fort  Union  are  given  in  most  of  the 
United  States  Geological  Survey  publications  dealing  with  Eastern 
Montana.  One  of  the  most  instructive  is  the  generalized  section  given 
by  Calvert (25)  of  the  Sidney  lignite  field. 

The  Fort  Union  contains  a very  large  flora,  approximately  500 
species(26),  generally  acknowledged  to  be  Eocene.  It  has  a far  less 
abundant  fauna,  consisting  of  fresh  water  shells,  some  vertebrates,  and 
even  small  mammals,  that  is  less  generally  believed  to  be  Eocene. 
The  plants  and  shells  as  well  as  the  numerous  coal  seams  indicate, 
however,  that  the  Fort  Union  was  deposited  in  fresh  or  nearly  fresh 
water,  presumably  in  inland  streams  and  lakes,  and  possibly  in 
estuaries. 

Lance  formation. — The  name  Lance  formation,  first  used  by  Stan- 
ton(27)  is  an  abbreviated  form  of  the  term  “ Lance  Creek  beds”  used 
by  Hatcher(28)  to  designate  what  had  been  previously  called  the 
“Ceratops  beds”  of  the  Laramie.  Since  Stanton’s  use  of  the  term  in 
1910,  all  of  the  rocks  underlying  the  Fort  Union  and  overlying  the 
Bearpaw  shales  or  the  Fox  Hills  sandstone  have  been  called  Lance,  and 
none  of  the  rocks  of  Central  and  Eastern  Montana  have  any  longer 
been  referred  to  the  Laramie. 

The  Lance  formation  outcrops  so  as  to  form  a broad  belt,  3 to  60 
miles  wide,  averaging  25  miles  wide,  between  the  predominating  Fort 
Union  rocks  of  Eastern  Montana  and  the  predominating  Mesozoic 
rocks  of  Central  Montana.  It  is  further  exposed  in  Eastern  Montana 
along  the  larger  rivers  and  on  the  flanks  of  the  larger  uplifts,  the 
Cedar  Creek  anticline  and  the  northern  extension  of  the  Black  Hills 
uplift,  and  at  the  crests  of  the  smaller  uplifts,  like  the  Coal  Creek 
dome,  Scobey  anticline,  and  Big  Muddy  Creek  dome.  In  Central  Mon- 
tana, south  of  the  Little  Belt-Big  Snowy  anticlinorium,  the  formation 


(23)  Woodruff,  E.  G.,  Red  Lodge  coal  field,  Montana:  U.  S.  Geol.  Survey, 
Bull.  341,  p.  94,  1909. 

(24)  Stone,  R.  W.,  Coal  near  the  Crazy  Mountains,  Montana:  U.  S.  Geol.  Sur- 
vey, Bull.  341,  p.  82,  1909. 

(25)  Calvert,  W.  R.,  Geology  of  certain  lignite  fields  in  eastern  Montana:  U.  S. 
Geol.  Survey,  Bull.  471,  p.  199,  1912. 

(26)  Knowlton,  F.  H.,  Science,  April  1,  1921,  p.  307. 

(27)  Stanton,  T.  W.,  Fox  Hills  sandstone  and  Lance  formation  in  South  Dakota, 
North  Dakota,  and  eastern  Wyoming:  Am.  Jour.  Sci.,  4th  ser.,  vol.  30,  p.  172,  1910. 

(28)  Hatcher,  J.  B.,  Relative  age  of  the  Lance  Creek  beds  of  Converse  County, 
Wyo.,  the  Judith  River  beds  of  Montana,  and  the  Belly  River  beds  of  Canada  ; Ann. 
Geologist,  vol.  31,  p.  369,  1903. 


30 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


PLATE  IV.— LANCE  FORMATION. 


A typical  exposure  of  the  Lance  formation  showing  the  white  basal  member.  Colgate 
sandstone,  and  the  overlying  somber-colored  shales  and  sands.  Sec.  8. 

T.  19  N..  R.  29  E. 


LANCE  FORMATION 


31 


is  exposed  around  the  flanks  of  the  Bull  Mountain  syncline,  and 
underlies  the  greater  part  of  the  synclinal  area  between  the  major 
anticlinal  axis  and  the  main  front  range  of  the  Rocky  Mountains. 
There  are  also  a few  small  outliers  between  the  two  synclinal  areas. 
North  of  the  anticlinorijim  the  Lance  forms  two  synclinal  areas,  one 
south  of  the  Little  Rocky  Mountains  uplift  and  the  other  to  the 
north,  extending  into  Canada.  Between  the  Sweetgrass  arch  and  the 
main  front  range,  the  rocks  of  the  St.  Mary  River  and  Willow  Creek 
formations,  referred  by  Stebinger(29)  to  the  Tertiary(?)  Eocene(?), 
and  also  the  Horsethief  formation  of  Cretaceous  age,  have  been  mapped 
by  the  authors  as  the  equivalent  of  the  Lance. 

The  Lance  formation  is  composed  of  alternating  beds  of  dull 
grayish  to  greenish  yellow,  soft  to  hard  sandstones,  greenish  to  gray 
sandy  shale,  drab,  yellow,  gray,  and  in  a few  places  brown  clays, 
and  clay-shale.  In  most  places  the  sandy  rocks  predominate  and  the 
prevailing  dull  neutral  colors  have  given  rise  to  the  name  “somber 
beds.  ” West  of  the  Sweetgrass  arch,  the  St.  Mary  River  formation  is 
chiefly  maroon  to  chocolate  brown  in  color,  so  that  the  formation  has 
a predominating  brownish  red  appearance,  due  partly  to  the  covering 
of  red  soil. 

The  sandstones  are  noticeably  harder,  coarser  grained,  even  arkosic 
and  conglomeratic  in  places,  and  more  massive  in  the  lower  part 
of  the  formation.  In  the  upper  part  there  are  numerous  carbonaceous 
layers  and  a few  relatively  thin  and  non-persistent  seams  of  impure 
lignite  and  high-ash  coal.  At  least  in  the  northeastern  and  north- 
western parts  of  the  Lance  area  in  Montana  there  are  a few  rela- 
tively thin  lentils  of  impure  limestone (30).  The  sandstones,  particu- 
larly the  lower  and  more  massive  ones,  are  cross  bedded  and  ripple 
marked,  and  contain  numerous  dark  brown,  iron  stained  concretions, 
some  spherical  and  rounded,  others  cylindrical  and  log-like  up  to  large 
sizes,  3 feet  in  diameter  and  20  to  30  feet  long. 

Although  the  Lance  formation  in  most  places  is  readily  divided 
into  three  subdivisions,  a lower  part  consisting  chiefly  of  massive 
sandstone,  a middle  part  of  alternating  clays  and  soft  sandstones, 
and  an  upper  carbonaceous  or  lignitic  part,  yet  it  was  not  feasible  to 
make  the  subdivision  during  rapid  reconnaissance  mapping.  The  lower 
massive  sandstones  contain  in  several  places  an  undoubted  Cretaceous 
marine  fauna  and  are  best  considered  as  of  Fox  Hills  age.  Fox  Hills 
beds  have  been  definitely  determined  bordering  the  Cedar  Creek  anti- 
nicle  just  east  of  the  Montana  line  in  North  and  South  Dakota(31), 
but  the  same  beds  have  been  included  in  the  Colgate  sandstone  mem- 


(29)  Stebinger,  Eugene,  Geology  and  coal  resources  of  northern  Teton  County, 
Montana:  U.  S.  Geol.  Survey,  Bull.  621-K,  p.  124,  1916. 

(30)  Smith,  C.  D.,  The  Fort  Peck  Indian  Reservation  lignite  field,  Montana: 
U.  S.  Geol.  Survey,  Bull.  381-A,  p.  43,  1910,  and  Stebinger,  Eugene,  Op.  Cit.  p.  27. 

(31)  Winchester,  D.  E.,  et  al.,  The  lignite  field  of  northwestern  South  Da- 
kota: U.  S.  Geol.  Survey,  Bull.  627,  pp.  17-18,  1916. 


32 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


ber  of’ the  Lance  formation  in  Montana(32).  The  sandstones  and  shales 
overlying  the  Bearpaw  shales  along  the  Missouri  River  north  of  Jordan, 
have  also  been  referred  to  the  Fox  Hills  sandstone  by  Leonard(33). 

In  the  upper  Musselshell  Valley,  an  assemblance  of  andesitic  sand- 
stones and  dark  shale  between  the  Bearpaw  and  Lance  formations 
has  been  designated  as  the  Lennep  sandstone  (34).  The  fossil  shells 
found  in  the  formation  are  about  equally  fresh,  brackish  water,  and 
marine,  and  are  more  closely  related  to  the  Cretaceous  than  to  the 
Tertiary.  It  occupies  the  stratigraphic  portion  of  the  Fox  Hills  and 
has  been  included  in  this  report  with  the  other  basal  members  of  the 
Lance. 

In  the  northeastern  part  of  Central  Montana,  the  Horsethief  sand- 
stone overlies  the  Bearpaw  shale  and  underlies  the  Tertiary  (?)  forma- 
tions. It  consists  chiefly  of  a sandstone,  which  becomes  shaly  toward 
the  base,  and  to  the  south  near  Augusta,  contains  some  conglomerate 
with  well  rounded  pebbles  of  fine  grained  igneous  rock.  In  places  the 
sandstone  is  exceedingly  fossiliferous,  some  beds  being  almost  entirely 
composed  of  oyster  and  other  shells.  The  fauna  is  Cretaceous  and  of 
both  brackish  water  and  true  marine,  although  near-shore  types(35). 
This  formation  has  also  been  included  in  this  report  with  the  other 
basal  members  of  the  Lance. 

The  upper  lignitic  portion  of  the  Lance  is  doubtless  best  cor- 
related with  the  Ludlow  lignitic  member  of  the  Dakotas (36).  How- 
ever, in  reconnaissance  mapping,  as  already  mentioned,  the  contact 
between  the  Lance  and  Fort  Union,  where  not  marked  by  the  Lebo 
shale  was  placed  at  the  contact  of  the  beds  of  dull  and  bright  colors, 
or  at  the  lowest  persistent  coal  seam,  both  of  which  vary  considerably 
in  position.  As  a result,  most  of  the  beds  in  Montana  of  the  same 
horizon  as  the  Ludlow  lignitic  member  have  been  placed  in  the  Fort 
Union. 

Like  the  Fort  Union  rocks,  those  of  the  Lance  formation  are  well 
exposed  south  of  the  area  covered  by  glacial  drift.  Furthermore, 
where  flat  lying,  the  sandstones  form  buttes,  mesas,  or  series  of 
scarps,  50  to  100  feet  high,  whereas,  the  shales  weather  into  smooth, 
gentle  slopes  and  rounded  buttes,  and  in  favorable  places  into  bad 
land  topography.  Where  more  steeply  dipping,  the  sandstones  form 
cuestas  and  hogbacks,  separated  by  narrow  valleys  cut  in  the  soft 
shales. 

The  basal  sandstone  of  the  Lance  formation  is  thickest  near 
the  mountains  and  thins  slightly  to  the  east.  In  the  northwestern 


(32)  Calvert,  W.  R.,  Geology  of  certain  lignite  fields  in  eastern  Montana:  U.  S. 
Geol.  Survey,  Bull.  471,  pp.  189  and  194-195,  1912. 

(33)  Leonard,  A.  G.,  The  Cretaceous  and  Tertiary  formations  of  -western  North 
Dakota  and  eastern  Montana:  Jour.  Geol.,  vol.  19,  p.  515,  1911. 

(34)  Stone,  R.  W.,  and  Calvert,  W.  R.,  Stratigraphic  relations  of  the  Livingston 
formation  of  Montana:  Econ.  Geol.,  vol.  5,  p.  746,  1905. 

(35)  Stebinger,  Eugene,  The  Montana  group  of  northwestern  Montana:  U.  S. 
Geol.  Survey  Prof.  Paper  90-G,  p.  62,  1914. 

(36)  Winchester,  D.  E.,  et  al.,  The  lignite  field  of  northwestern  South  Dakota: 
U.  S.  Geol.  Survey,  Bull.  627,  pp.  19-22,  1916. 


LANCE  FORMATION 


33 


part  of  Central  Montana  the  Horsethief  sandstone  varies  from  250  to 
400  feet  thick.  In  the  upper  Musselshell  Valley,  the  Lennep  sandstone 
is  315  feet  thick.  Farther  east  the  Colgate  and  Fox  Hills  sandstone 
varies  in  thickness  from  50  to  200  feet.  In  like  manner  the  upper 
part  of  the  Lance  thins  eastward,  but  more  noticeably.  Along  the 
mountain  front,  the  upper  Lance  varies  from  1400  to  1700  feet  thick. 
It  thins  so  rapidly  to  the  east  that  it  is  700  to  800  feet  thick  in  east 
Central  Montana,  500  feet  in  southeastern  Montana,  and  only  200  feet 
thick  in  northeastern  Montana. 

Detailed  sections  are  given  in  nearly  all  of  the  United  States  Geo- 
logical Survey  publications  dealing  with  the  Lance  formation,  but  vary 
so  from  place  to  place  that  they  are  of  little  value  in  a general  descrip- 
tion. 

The  Lance  formation  like  the  Fort  Union,  contains  a rich  flora, 
comprising  about  125  forms,  of  which  87  species (37)  have  been  posi- 
tively identified.  Invertebrate  fossils  are  not  numerous  except  in  the 
basal  marine  beds.  On  the  other  hand,  numerous  fossil  vertebrates, 
the  most  striking  of  which  si  the  large  three-horned  Triceratops,  have 
been  found.  It  is  quite  certain  that  in  places  a portion  of  the  basal 
beds  seem  to  have  been  deposited  in  fresh  or  brackish  waters.  Cross 
bedding  and  ripple  marks  indicate  deposition  by  streams  and  in  places, 
even  by  wind.  In  Montana  the  upper  beds  appear  to  have  been 
entirely  of  continental  or  fresh  water  origin,  having  been  deposited  in 
streams,  lakes  and  possibly  estuaries. 


(37)  Knowlton,  F.  H.,  Science,  p.  307,  April  1,  1921. 


MESOZOIC  AND  PALEOZOIC 
SYSTEMS 

BY 

ARTHUR  BEVAN 

Since  it  is  the  purpose  of  this  part  of  the  report  to  present  the 
principal  features  of  the  Mesozoic  stratigraphy  of  the  Montana  Great 
Plains  the  observations  of  the  writer  and  other  members  of  the  State 
Bureau  of  Mines’  field  parties  have  been  rather  freely  supplemented 
by  the  use  of  data  from  the  published  reports  upon  the  region.  Num- 
reous  publications  have  appeared,  mainly  from  the  United  States  Geo- 
logical Survey,  which  treat  of  particular  districts,  although  a few 
discuss  stratigraphic  units,  but  so  far  the  great  body  of  data  afforded 
by  the  many  field  studies  have  not  been  conveniently  assembled. 
Although  the  Mesozoic  formations  are  here  discussed  in  some  detail 
the  treatment  is  by  no  means  exhaustive.  The  Paleozoic  formations, 
in  so  far  as  they  appear  in  this  province,  are  discussed  briefly  with 
reference  to  the  features  that  have  a bearing  upon  the  petroleum 
resources  of  the  state.  The  articles  which  have  been  consulted  are 
listed  in  the  bibliography,  and  foot-note  references  to  sources  are 
made  wherever  appropriate. 

THE  MESOZOIC 

Formations  of  Mesozoic  age  appear  at  the  surface  or  underlie 
the  surficial  mantle  of  alluvium  and  glacial  drift  throughout  approxi- 
mately half  of  the  Great  Plains  province  in  Montana.  They  cover 
all  the  area  north  of  the  Missouri  River  from  the  Rocky  Mountains 
to  Eastern  Montana,  with  the  exception  of  limited  areas  of  Lance 
sediments  adjacent  to  the  mountain  front,  igneous  rocks  in  the  Bear- 
paw  Mountains,  the  Sweetgrass  Hills,  and  the  Little  Rocky  Mountains, 
and  Paleozoic  sediments  in  the  last  two  uplifts.  The  area  between 
Missouri  River  on  the  north,  Rocky  Mountains  on  the  west,  and  Mus- 
selshell and  Little  Bighorn  rivers  on  the  east  is  occupied  mainly  by 
Mesozoic  sediments.  A broad  tongue  reaches  southeast  from  this  area 
in  the  vicinity  of  Mosby  on  Musselshell  River  into  Yellowstone  Valley 
west  of  Forsyth,  while  a parallel  embayment  of  Lance  and  Fort  Union 
rocks  extend  northwest  from  this  point  through  Bull  Mountains  and 
across  Musselshell  Valley  beyond  Roundup.  Another  broad  area  of 
Lance  and  Fort  Union  formations  covers  the  Mesozoic  along  the 
Rocky  Mountain  front  from  the  Crazy  Mountains  to  the  Wyoming 
boundary.  Elsewhere  in  this  part  of  the  state  the  surface  continuity 


MESOZOIC  FORMATIONS 


35 


of  the  Mesozoic  is  interrupted  only  by  the  isolated  mountain  uplifts, 
scattered  outliers  of  younger  sediments,  or  a relatively  thin  mantle 
of  unconsolidated  materials. 

The  Mesozoic  group  is  now  commonly  separated  into  four  sub- 
divisions: The  Triassic,  Jurassic,  Comanchean,  and  Cretaceous  systems, 

all  of  which  are  present  in  the  plains  portion  of  the  state (38).  In 
this  region  it  includes  the  formations  that  are  between  the  Quadrant 
formation  below  and  the  Lance  formation  above.  The  Triassic  is 
meagerly  present,  being  restricted  to  the  flanks  of  the  Bighorn  and 
Pryor  mountains,  where  it  consists  of  the  Chugwater  formation,  or 
“Red  Beds. ” The  Ellis  formation,  which  is  the  main  representative 
of  the  Jurassic  system,  is  exposed  only  along  the  borders  of  the  sev- 
eral mountain  uplifts  in  Central  Montana.  It  is  overlain  and  par- 
alleled in  outcrop  by  the  Morrison  formation  which  appears  to  be 
transitional  between  the  Jurassic  and  Comanchean  systems.  The  latter 
is  represented  maiqly  by  the  Kootenai  formation  which  has  a surface 
distribution  similar  to  that  of  the  Ellis  formation  but  has  a wider 
outcrop  due  to  its  greater  thickness  and  gentler  dips.  Overlying  it  is 
the  Colorado  shale  of  Cretaceous  age,  with  vast  areal  extent  in  the 
Sweetgrass  arch,  and  less  extensive  exposures  in  several  of  the  major 
uplifts.  The  remaining  formations  of  this  system  are  included  in  the 
Montana  group  and  consist  of  the  Eagle  sandstone  at  the  base,  the 
Claggett  formation,  the  Judith  River  formation,  and  the  Bearpaw  shale. 
These  formations,  or  their  equivalents,  occupy  a considerable  part  of 
Central  Montana.  In  the  northwestern  portion  the  upper  part  of  the 
Eagle  sandstone  and  the  other  formations  below  the  Bearpaw  shale  are 
included  in  the  Two  Medicine  formation.  The  Livingston  formation, 
which  is  partly  of  undoubted  Cretaceous  and  partly  of  Lance  age,  bor- 
ders the  Crazy  Mountains  and  extends  southeasterly  beyond  the  Yel- 
lowstone Valley. 

The  Mesozoic  formations  are  very  largely  composed  of  elastic 
sediments,  mainly  sandstones  and  shales,  of  which  the  latter  are 
greatly  preponderant.  A striking  feature  of  the  sequence  is  the  alter- 
ation of  shale  and  sandstone  formations,  each  of  which  has  persistent 
lithologic  homeogeneity.  As  a rule  pronounced  intercalation  of  the 
one  kind  of  sediment  in  the  other  is  rare  except  in  a few  places. 
Thin  limestones  occur  sparingly  but  are  mainly  confined  to  the  Ellis 
formation  with  local  lenses  and  thin  beds  in  the  Kootenai  formation. 
Coal  is  widespread  and  abundant  in  some  of  the  formations,  espe- 
cially in  the  Kootenai,  although  workable  beds  are  present  in  several 
places  in  the  Eagle,  Judith  River,  and  Two  Medicine  formations. 
The  Chugwater  formation  contains  thick  gypsum  beds  at  several  locali- 
ties. Igneous  material  is  present  in  the  Mesozoic  group  only  in  the 
form  of  tuffaceous  beds  intermixed  with  variable  amounts  of  sedi- 
ment at  several  horizons,  chief  of  which  is  the  Livingston  formation. 

(38)  Comanchean.  is  here  used  as  the  equivalent  of  the  former  ‘‘Lower  Cre- 
taceous” in  accordance  with  the  prevailing  current  usage. 


36 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


Inasmuch  as  the  different  formations  vary  in  thickness  from 
place  to  place  throughout  the  state  as  well  as  being  either  partially 
removed  by  erosion  or  deeply  buried  in  any  particular  area,  it  is 
somewhat  difficult  to  estimate  the  total  thickness  jof  the  Mesozoic 
sediments.  However,  it  may  be  roughly  placed  between  2400  feet  as 
a minimum  and  8800  feet  as  a maximum.  This  includes  all  the  Meso- 
zoic formations  of  sedimentary  origin  no  matter  how  widely  separated 
the  most  complete  or  the  thickest  sections  may  be.  The  thickest  more 
or  less  continuous  sections  that  have  been  measured  are  in  north- 
western part  of  Central  Montana,  in  the  vicinity  of  Bighorn  Moun- 
tains, and  in  Musselshell  Valiev,  where  a total  of  7000,  5700,  and 
4700  feet  respectively  have  been  reported(39). 

THE  CRETACEOUS  SYSTEM. 

Formations  of  Cretaceous  age  occupy  by  far  the  greater  part  of 
the  vast  aiea  over  which  Mesozoic  sediments  constitute  the  surface 
formations.  The  only  places  where  older  rocks  crop  out  are  in  the 
mountain  uplifts  and  over  rather  limited  tracts  adjoining  a few  of 
them. 

The  subdivisions  of  the  Cretaceous  system  (as  the  term  is  here 
used)  in  the  northern  Black  Hills  and  the  adjacent  Great  Plains  are 
as  follows:  Dakota  sandstone  at  the  base,  Benton  group,  Niobrara 
formation,  and  Pierre  shale (40).  Farther  north  in  South  Dakota  the 
Pierre  is  overlain  by  the  Fox  Hills  sandstone  which  constitutes  the 
youngest  formation  of  positive  Cretaceous  age  in  this  province.  Some 
of  the  early  surveys  in  mapping  the  Cretaceous  formations  of  the 
Rocky  Mountains  and  the  bordering  Great  Plains  of  Montana  used 
the  divisions,  Dakota,  Colorado,  and  Montana,  although  the  term  Ben- 
ton was  widely  used  for  the  shales  above  the  so-called  Dakota  sand- 
stone. 

Recent  extensive  detailed  examination  by  the  U.  S.  Geological 
Survey  of  many  Cretaceous  areas  in  the  state  has  apparently  demon- 
rtsated  beyond  reasonable  question  that  the  Dakota  sandstone  is  no- 
where present  in  this  state.  Thus  it  is  erroneous  and  misleading  to 
call  any  beds  in  Montana  the  “Dakota  sandstone ’ ’(41).  Inasmuch 
as  the  Niobrara  can  not  be  recognized  in  Montana  as  a distinct  unit 
and  the  section  between  the  Kootenai  and  the  basal  Montana  includes 
more  than  the  typical  Benton  group  the  use  of  the  latter  term  has 
become  inappropriate.  It  has  therefore  been  supplanted  by  the  Colo- 


(39)  Stebinger,  Eugene,  Geology  and  coal  resources  of  northern  Teton  County, 
Montana:  U.  S.  Geol.  Survey,  Bull.  621-K,  p.  124,  1916;  Hares,  C.  J.,  unpublished 
data,  and  Darton,  N.  H.,  Geology  of  Bighorn  Mountains:  U.  S.  Geol.  Survey  Prof. 
Paper  51,  Plate  VI,  1906;  and  Reeves,  Frank,  Press  Report  U.  S.  Geol.  Survey, 
1921. 

(40)  Darton,  N.  H.,  and  O’Hara,  C.  C.,  U.  S.  Geol.  Survey  Geol.  Atlas,  Aladdin 
folio(No.  128),  1905. 

(41)  The  same  criticism  probably  applies  to  the  Cretaceous  classification  of 
icuti.crn  Alberta,  where  the  t.rm  ‘Dakota’’  has  persisted  from  the  early  surveys. 
See  Stebinger,  Eugene,  U.  S.  Geol.  Survey,  Bull.  641-C,  pp.  61-62,  1916. 


MONTANA  GROUP 


37 


rado  for  the  lower  part  of  the  Cretaceous  section.  The  Montana 
group  of  this  state  appears  to  be  the  equivalent  of  the  Pierre  of 
South  Dakota  and  may  include  also  the  Fox  Hills  sandstone  of  that 
region.  Hence  at  the  present  time  the  two-fold  division . of  the  Cre- 
taceous into  the  Colorado  shale  and  the  Montana  group  is  accepted 
for  Montana.  The  Montana  group  has  been  further  subdivided 
throughout  the  state,  and  these  divisions  are  discussed  below. 

THE  MONTANA  GROUP. — The  Montana  group  includes  all  for- 
mations of  undoubted  Cretaceous  age  above  the  Colorado  shale.  The 
term  was  first  applied  by  Eldridge  to  the  Fort  Pierre  and  Fox  Hills 
formations  near  Denver,  Colorado(42),  and  later  to  the  similar  section 
in  the  Bighorn  Basin  in  northwestern  Wyoming  and  southern  Mon- 
tana(43).  Throughout  the  greater  part  of  the  region  this  group  con- 
sists of  Eagle  sandstone  at  the  base,  Claggett  formation,  Judith  River 
formation,  and  Bearpaw  shale,  each  of  which  forms  a distinct  litho- 
logic unit.  The  Claggett  and  Bearpaw,  however,  are  so  nearly  identi- 
cal in  many  places  that  they  can  be  distinguished  only  by  noting  the 
stratigraphic  sequence.  There  is  no  difficulty  in  doing  this  if  the 
prominent  Lance  sandstones  are  taken  as  a datum  plane,  or  if  the 
Colorado  shale  and  Eagle  sandstone  are  recognized.  The  Eagle  and 
Judith  River  sandstones  are  somewhat  dissimilar  but  may  be  mis- 
taken for  each  other  in  areas  of  obscure  outcrops.  The  best  method, 
then,  of  identifying  the  several  formations  of  this  group  is  to  note 
the  succession  carefully.  Where  the  strata  are  steeply  dipping  this 
can  be  done  by  a glance  at  the  topography,  as  the  Claggett  and 
Bearpaw  will  then  occupy  conspicuous  depressions  between  prominent 
sandstone  ridges.  These  sandstones  are  invaluable  aids  in  deciphering 
the  structure  of  many  areas,  for  the  shales  of  this  group  seldom  ex- 
hibit bedding  clearly. 

With  a change  in  the  nature  of  the  sediments  in  the  northwestern 
part  of  Central  Montana  the  divisions  of  the  Montana  group  become 
Virgelle  sandstone,  Two  Medicine  formation,  and  Bearpaw  shale.  In 
this  section  the  Virgelle  and  the  overlying  Horsethief  are  the  best 
key  horizons.  These  two  sandstones  are  nearly  identical  in  composi- 
tion and  appearance  but  they  can  be  readily  distinguished  by  means 
of  their  distribution  and  stratigraphic  relations. 

In  some  areas  it  is  almost  impossible  to  identify  with  certainty 
any  particular  division  of  the  Montana  group  owing  to  the  meager 
and  widely  scattered  outcrops  of  formations  which  change  markedly 
in  lithology  within  short  distances.  The  difficulty  is  greatly  increased 
by  the  existence  of  complex  structure,  due  to  pronounced  folding  or 
faulting,  which  has  been  generally  concealed  by  widespread  deposits 
of  glacial  drift  or  terrace  gravels.  Such  tracts  exist  at  several  places, 

(42)  Eldridge,  G.  H.,  Method  of  grouping  the  formations  of  the  Middle  Cre- 
taceous: Am.  Jour.  Sci.,  3d  ser.,  vol.  38,  pp.  313-321,  1889. 

(43)  Eldridge,  G.  H.,  A geological  reconnaissance  in  northwest  Wyoming:  U.  S. 
Geol.  Survey,  Bull.  119,  pp.  23-24,  1894. 


38 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


chiefly  in  the  northwestern  part  of  Central  Montana.  For  mapping 
purposes  the  problem  has  been  solved  by  designating  such  areas  as 
“ Montana  undivided.  ” There  are  a few  other  areas,  as  in  the  Big- 
horn Basin,  where  the  typical  characteristics  of  the  individual  forma- 
tions change  to  such  an  extent  that  the  Montana  group  can  not  be 
subdivided  without  a detailed  survey  of  the  region.  The  term  “Mon- 
tana undivided”  is  likewise  used  here  in  mapping  the  entire  group 
or  such  part  of  it  as  may  be  present. 

The  thickness  of  the  Montana  group  is  so  considerable  that  it 
can  not  be  determined  readily  at  a single  locality  or  even  in  a small 
area.  Complete  sections  that  have  been  measured  along  the  north- 
west side  of  Elk  Basin  and  near  Bridger,  in  Carbon  County,  where 
the  group  appears  to  be  the  thinnest,  give  a thickness  of  1185  and 
1069  feet  respectively (44).  A more  recent  measurement  of  the  for- 
mations in  Elk  Basin  gives  a thickness  of  approximately  1815 
feet  to  the  Montana,  but  it  appears  that  the  summit  of  the  Bearpaw 
has  been  taken  at  a higher  horizon (45).  A generalized  section  shows 
a thickness  of  1750  feet  in  Lake  Basin,  2000  to  3050  feet  in  Mussel- 
shell Valley,  2050  to  2275  feet  in  Phillips  County  and  3020  feet  in 
Glacier  County. 

Bearpaw  shale. — The  name  Bearpaw  shale  was  first  applied  to 
the  thick  body  of  shale  that  forms  the  upper  part  of  the  Montana 
group  on  the  flanks  of  the  Bearpaw  Mountains (46).  As  a result  of 
its  stratigraphic  position  and  the  widespread  erosion  of  younger  for- 
mations it  probably  has  a greater  areal  extent  than  any  other  Mesozoic 
formation.  It  is  continuously  exposed  over  thousands  of  square  miles 
in  the  east-  and  south-central  parts  of  the  state  and  is  present  imme- 
diately beneath  the  mantle  of  glacial  drift  over  a vast  area  north  of 
the  Missouri  River.  It  is  exposed  along  the  valley  of  the  lower  Mus- 
selshell River  and  from  there  southeastward  to  the  Porcupine  dome. 
Another  extensive  area  exists  in  Lake  Basin  northwest  of  Billings 
from  which  it  crosses  Yellowstone  Valley  east  of  Huntley  and  stretches 
southward  between  the  Bighorn  and  Little  Bighorn  rivers.  In  the 
northwestern  part  of  the  region  it  occurs  on  the  west  flank  of  the 
Sweetgrass  arch.  The  broad  expanse  of  Lance  and  Fort  Union  in  the 
eastern  part  of  the  state  is  undoubtedly  underlain  by  it,  as  is  shown 
by  the  belt  of  Bearpaw  shale  that  surrounds  the  Porcupine  dome,  the 
belt  of  similar  shale  (Pierre)  along  the  axis  of  the  Cedar  Creek  anti- 
cline, southeast  of  Glendive,  and  the  extensive  area  in  southeastern 
Montana. 

Throughout  the  greater  part  of  the  area  which  it  occupies  the 
Bearpaw  shale  rests  upon  the  Judith  River  formation,  but  in  the 

(44)  Fisher,  C.  A.,  Southern  extension  of  the  Kootenai  and  Montana  coal  hear- 
ing formations  in  northern  Montana:  Econ.  Geol.,  vol.  3,  pp.  94-96,  1908. 

(45)  Section  measured  by  C.  J.  Hares  and  quoted  by  E.  T.  Hancock.  U.  S. 
Geol.  Survey,  Bull.  691,  p.  1.  XVII,  1918. 

(46)  Stanton,  T.  W.,  and  Hatcher,  J.  B.,  Scence,  new  ser.,  vol.  18,  p.  212, 
1903.  See  also,  U.  S.  Geol.  Survey  Bull.  257,  p.  13,  1905. 


BEARPAW  SHALE 


39 


northwestern  part  of  Central  Montana  it  overlies  the  Two  Medicine 
formation(47).  In  the  latter  area  it  lies  beneath  the  Horsethief  sand- 
stone; in  the  Musselshell  Valley  from  Lavina  westward  it  is  imme- 
diately below  the  Lennep  sandstone;  while  elsewhere  it  underlies  the 
Lance  formation. 

The  Bearpaw  shale  is  typically  a dark  gray,  clayey  shale  that 
weathers  into  a distinctive  alkaline,  infertile  gumbo  soil.  Small  crys- 
tals and  crystalline  flakes  of  gypsum  are  abundant  throughout  the 
formation,  being  especially  noticeable  upon  the  weathered  slopes.  In 
consequence  of  the  abundance  of  gypsum,  water  from  the  formation  is 
commonly  too  alkaline  for  domestic  use.  Concretions  of  dark  gray, 
fine-grained  limestone  are  sparsely  scattered  through  the  shale  in  most 
places  but  in  places  they  are  grouped  in  bands  or  zones.  They  weather 
reddish-brown  on  the  surface  and  after  long  exposure  crumble  to  a 
scattered  mass  of  small  angular  fragments  which  somewhat  protect  the 
shale  at  that  place  from  erosion.  Many  of  these  concretions  contain 
much  sideritic  calcite,  and  cone-in-cone  structure  is  rarely  present.  As 
a rule  they  are  one  to  two  feet  in  diameter  but  some  as  large  as  12 
to  15  feet  have  been  reported  southeast  of  Havre(48). 

In  some  districts  the  Bearpaw  becomes  distinctly  sandy  either  in 
zones  or  throughout  most  of  the  formation  and  thus,  to  a greater  or 
less  extent,  loses  its  characteristic  lithologic  nature.  One  phase  of  this 
change  is  well  shown  in  the  Lake  Basin  field(49).  Here  several  sand- 
stone beds  appear  at  various  horizons  and  form  conspicuous  ledges  and 
gentle  dip-slopes  that  break  the  monotony  of  the  subdued  topography 
that  is  generally  developed  on  the  shale.  Sandy  shales  and  sandstones 
are  especially  prominent  as  the  adjacent  formations,  particularly  the 
Judith  River,  are  approached,  but  occur  in  some  localities  well  within 
the  main  mass  of  typical  Bearpaw  shale.  These  sandstones  are  com- 
monly yellowish  though  locally  a layer  is  white.  They  are  rather 
coarse-grained  with  local  thin  conglomerates,  as  a rule  strongly  cross- 
bedded,  and  contain  plentiful  plant  remains  in  a more  or  less  frag- 
mentary condition.  Some  of  the  sandstones  in  many  places  weather 
into  great  numbers  of  conspicuous,  hard,  flattish,  rusty  concretions. 
A notable  peculiarity  in  certain  portions  of  Lake  Basin  is  the  occur- 
rence of  andesitic  sandstones  that  cap  long  narrow  ridges.  Subordinate 
amounts  of  tuffaceous  material  are  present  at  various  horizons.  An- 
other noteworthy  feature  here  is  carbonaceous  shale  which  passes 
locally  into  beds  of  lignite  about  a foot  thick.  There  is  considerable 
lateral  variation  in  this  field  in  the  nature  of  the  sediments,  even  in 
short  distances,  sandstones  frequently  giving  way  to  typical  clay  shale 
in  the  same  ridge  or  a thick  section  of  dominantly  sandy  beds  in  one 


(47)  The  upper  part  of  the  Two  Medicine  formation  is  equivalent  to  the  Judith 
River  formation. 

(48)  U.  S.  Geol.  Survey  Bull.  257,  p.  48,  1905. 

(49)  Hancock,  E.  T.,  Geology  and  oil  and  gas  prospects  of  the  Lake  Basin  field, 
Montana:  U.  S.  Geol.  Survey  Bull.  691-D,  1918. 


40 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


place  may  be  replaced  near  by  with  a sequence  of  interbedded  thin 
sandstones  and  thick  shales. 

The  sandy  phase  of  the  Bearpaw  is  exhibited  west  of  the  Lake 
Basin  district  between  Harlowton  and  Big  Timber  and  in  Yellowstone 
Valley  west  of  Columbus.  In  this  region  the  sandstones  become  so 
preponderant  that  it  is  only  by  careful  tracing  of  the  formation  from 
its  typical  development  east  of  here  that  it  can  be  separated  from 
the  underlying  Judith  River  or  the  overlying  Lance.  Farther  west 
and  southwest  the  strata  are  entirely  of  sandstone  and  pass  into  the 
so-called  Livingston  formation,  from  which  the  Bearpaw  can  be  differ- 
entiated, if  at  all,  only  by  persistent  detailed  work. 

A somewhat  similar  change  takes  place  in  the  northwestern  part 
of  Central  Montana  in  the  vicinity  of  Dupuyer  Creek  in  southern 
Pondera  County.  The  Bearpaw  is  typically  developed  north  of  here 
to  far  beyond  the  Canadian  boundary  while  to  the  south  the  “dark 
shale  grades  within  a short  distance  into  light-colored  sandstones  and 
clay  shale  that  are  identical  with  the  prevailing  materials  in  the  Two 
Medicine  formation  and  south  of  Dupuyer  Creek  can  not  be  separated 
from  that  formation  ”(50). 

Typical  exposures  of  the  Bearpaw  are  abundant  throughout  the 
area  where  it  appears  at  the  surface  but  owing  to  the  fact  that  it 
weathers  readily  extensive  sections  are  rare.  This  seeming  defect  is 
counterbalanced  by  the  homogeneity  of  the  formation  from  top  to 
bottom  in  its  typical  development,  and  thus  almost  any  cut  bank  in 
it  gives  a good  idea  of  the  whole  formation.  Several  detailed  sections 
of  the  sandy  phases  are  given  by  Hancock  in  the  Lake  Basin  field(51). 
A complete  section  is  shown  on  the  south  flank  of  an  anticline  along 
the  Harlowton-Big  Timber  road  in  the  southwestern  part  of  T.  15  E., 
R.  6 N.  Other  complete  sections  which  include  the  entire  underlying 
Judith  River  and  Claggett  formations  are  readily  accessible  along  the 
steeply  dipping  south  limb  of  the  Devil’s  Basin  anticline,  northeast 
of  Roundup. 

In  consequence  of  the  universal  occurrence  of  the  typical  Bear- 
paw between  two  prominent  sandstone  formations,  the  common  topo- 
graphic expression  of  the  much  weaker  shale  is  a marked  depression 
bounded  by  conspicuous  dip  slopes  or  escarpments.  This  is  especially 
true  where  the  dip  is  steep,  as  south  of  Lavina,  in  Musselshell  (now 
Golden  Valley)  County.  Where  the  strata  are  horizontal  or  nearly 
so  the  Bearpaw  area  is  generally  a monotonous  expanse  of  low  rounded 
ridges  and  hills  beyond  the  base  of  a more  or  less  prominent  Lance 
escarpment.  Resistant  sandstones  give  rise  in  places  to  ridges  and 
long  dip  slopes  within  the  formation  but  these  are  exceptional  outside 
of  the  Lake  Basin  district. 


(50)  Stebinger,  Eugene,  Oil  and  gas  geology  of  the  Birch  Creek- Sun  River 
area,  Northwestern  Montana:  U.  S.  Geol.  Survey  Bull.  691-E,  p.  166,  1918. 

(51)  Hancock,  E.  T.,  Geology  and  oil  and  gas  prospects  of  the  Lake  Basin  Field, 
Montana:  U.  S.  Geol.  Survey  Bull.  691-D,  pp.  121-123,  1918. 


JUDITH  RIVER  FORMATION 


41 


The  thickness  of  the  Bearpaw  has  been  measured  at  various  places 
throughout  the  state.  It  is  reported  in  the  northwestern  part  of  the 
region  to  have  a total  thickness  of  500  feet  which  increases  to  1000 
feet  in  Valley  County  and  reaches  a maximum  of  1150  feet  in  eastern 
Fergus  County.  Southward  from  here  the  formation  gradually  de- 
creases to  about  500  to  600  feet  in  Yellowstone  Valley  and  to  130  feet 
in  the  northern  part  of  Elk  Basin. 

The  Bearpaw  contains  an  abundant  fauna,  about  fifty  species  of 
marine  invertebrates  having  been  identified  from  various  collections 
in  it.  Most  of  the  fossils  occur  in  the  calcareous  concretions  and  be- 
come very  conspicuous  as  these  masses  crumble  upon  exposure  to  the 
weather.  Wherever  these  weathered  concretions  are  present,  a few 
specimens  can  nearly  always  be  found  and  on  many  slopes  several  spe- 
cies can  be  collected  in  a few  moments.  Such  a place  is  about  six 
miles  north  of  Melstone  in  Sec.  36,  T.  11  N.,  R.  30  E.  Other  typical 
localities  with  representative  lists  of  fossils  collected  therefrom  are 
given  in  several  previous  reports(52).  Of  these  numerous  forms, 
among  the  most  characteristic  are  Baculites  compressus,  Baculites 
ovatus,  and  Scaphites  ncdcsus,  but  species  of  Inoceramus,  Mactra, 
Ostrea,  and  Placenticeras  are  common.  This  invertebrate  fauna  is 
very  similar  to  that  of  the  underlying  Claggett  shale  but  differs  in 
that  the  fossils  are  more  abundant  and  the  species  are  more  diverse. 
Of  32  forms  listed  by  Bowen  from  the  Bearpaw  only  ten  are  present 
also  in  the  Claggett.  A few  fossils  other  than  invertebrates  have  been 
found  in  some  parts  of  the  state.  Scattered  remains  of  skeletons  of 
gigantic  marine  reptiles  have  been  collected  in  the  western  part  of 
Valley  County (53). 

E.  T.  Hancock  reports  an  abundance  of  Halymenites,  petrified 
wood,  and  stems  and  leaves  of  plants  from  the  sandstones  and  asso- 
ciated carbonaceous  shales  in  the  'Bearpaw  of  Lake  Basin(54). 

Judith  River  formation. — Except  in  the  northwestern  part  of 
the  Great  Plains  province  the  Bearpaw  shale  is  everywhere  underlain 
by  a series  of  sandstones  and  shales  which  has  long  been  known  as 
the  Judith  River  formation.  This  name  was  originally  applied  by 
F.  V.  Hayden  in  1871  to  typical  exposures  of  these  strata  near  the 
mouth  of  Judith  River (55),  but  it  was  not  until  more  than  thirty 
years  later  that  the  proper  position  of  the  formation  as  a member  of 
the  Montana  group  was  definitely  determined (56).  Since  then  there 
has  been  considerable  discussion  in  regard  to  the  exact  horizon  of 


(52)  U.  S.  Geol.  Survey  Prof.  Praper  90-1,  p.  102:  Prof.  Paper  120-B,  p.  30: 
Bull.  647,  p.  21. 

(53)  Collier,  A.  J.,  Geology  of  northeastern  Montana:  U.  S.  Geol.  Survey  Prof. 
Paper  120-B,  p.  30,  1918. 

(54)  Op.  cit.  pp.  121-122. 

(55)  Hayden,  F.  V.,  Geology  of  the  Missouri  Valley:  U.  S.  Geol.  Survey  Terr. 
Prelim.  (Fourth  Ann.)  Rept.,  p.  97,  1871. 

(56)  Stanton,  T.  W.,  and  Hatcher,  J.  B.,  Geology  and  paleontology  of  the  Judith 
River  beds:  U.  S.  Geol.  Survey  Bull.  257,  1905. 


42 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


Badlands  developed  in  the  flat-lying  Judith  River  formation  on  Rattlesnake  Creek, 


JUDITH  RIVER  FORMATION 


43 


these  beds  but  much  recent  detailed  work  has  confirmed  the  earlier 
conclusions  (57). 

The  areal  extent  of  the  Judith  Eiver  is  much  more  restricted  than 
that  of  the  Bearpaw.  Its  distribution  north  of  Missouri  River  is 
considerably  obscured  by  the  widespread  mantle  of  glacial  drift  but 
the  numerous  streams  have  cut  sufficiently  deep  in  many  places  to 
expose  the  formation  on  the  valley  slopes.  An  irregular  belt  of  it 
several  miles  wide  encircles  the  Bowdoin  dome,  from  which  a broad 
belt  extends  westward  far  up  Milk  Valley  beyond  Havre  toward  the 
Canadian  boundary.  Other  branches  which  reach  southward  from 
various  points  along  Milk  River  surround  the  Bearpaw  and  Little 
Rocky  mountains  before  uniting  in  the  broad  embayment  that  occu- 
pies Missouri  Valley  for  about  fifty  miles  below  the  mouth  of  Judith 
River.  The  main  outcrop  of  the  formation  continues  south  along  the 
east  side  of  Judith  Valley  and,  growing  rapidly  narrower  as  the  North 
Moccasin  and  Judith  mountains  are  approached,  swings  sharply  around 
their  north  slopes.  Here  it  strikes  southeasterly  as  a very  narrow 
band  along  the  north  limb  of  the  Cat  Creek  anticline,  then  swings 
around  the  east  ends  of  the  plunging  Cat  Creek,  Flatwillow,  and 
Devil’s  Basin  anticlines,  and  continues  west  along  the  steep  southern 
limb  of  the  latter.  It  is  exposed  at  several  places  south  of  the  Big 
Snowy  and  Little  Belt  mountains  and  on  the  flanks  of  numerous  local 
uplifts  in  Musselshell  Valley  as  far  west  as  Martinsdale.  From  this 
valley  is  continues  in  a southeasterly  direction  along  the  north  side 
of  Lake  Basin,  crosses  Yellowstone  River  between  Billings  and  Hunt- 
ley,  occupies  Bighorn  Valley  in  the  vicinity  of  Hardin,  then  swings 
south  along  the  east  side  of  the  Bighorn  uplift  to  the  Wyoming  boun- 
dary. A branch  of  this  belt  swings  around  the  east  end  of  Lake 
Basin,  crosses  Yellowstone  River  a few  miles  west  of  Park  City,  and 
follows  the  west  side  of  Bighorn  Basin  southward.  The  Judith  River 
is  the  surface  formation  in  the  Ingomar  and  McGinnis  Creek  domes 
and  forms  the  prominent  encircling  escarpment  of  the  broad  Porcupine 
dome.  It  also  surrounds  the  northern  extension  of  the  Black  Hills 
uplift. 

The  Judith  River  formation  consists  of  a series  of  alternating 
sandstones,  shales,  and  coal  beds  which  vary  greatly  in  relative  pro- 
portions and  sequence  from  place  to  place.  In  the  northern  part  of 
the  region  the  sandstones  are  commonly  soft  and  friable,  although 
locally  quite  hard,  light  gray  to  yellowish,  thin-bedded  to  massive, 
and  contain  numerous  iron  and  sandstone  concretions,  which  are  more 
abundant  in  the  basal  portion  of  the  formation.  The  sandstones  locally 
are  distinctly  cross-bedded  and  ripple-marked.  The  intercalated  shales 
are  predominantly  clayey  and  as  a rule  are  colored  with  tints  of  light 
gray  or  brown.  With  the  appearance  of  dark  gray  to  blackish  colors 
thick  beds  of  the  clay  shale  may  closely  resemble  the  Bearpaw  shale 


' (5?)  Bowen,  C.  F.,  The  stratigraphy  of  the  Montana  group:  U.  S.  Geol.  Survey 
Prof.  Paper  90-1,  1915. 


44 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


but  the  lack  of  characteristic  concretions  and  the  presence  of  thick 
sandstones  render  the  discrimination  less  difficult.  An  oyster  bed 
composed  of  shells  and  fragments  of  Ostrea  subtrigonalis  is  a common 
feature  near  the  top  of  the  formation  in  many  places,  and  where  pres- 
ent forms  an  excellent  horizon  marker.  Coal  beds  are  prominent  in 
some  areas,  such  as  in  Milk  River  Valley  between  Havre  and  Harlem, 
east  of  Big  Sandy,  on  the  northeast  side  of  the  Bearpaw  mountains, 
and  along  the  Missouri.  The  Judith  River  formation  contains  most 
of  the  coal  of  this  section  of  the  state,  but  some  is  present  in  the 
Eagle  and  in  a small  tract  of  Fort  Union  east  of  Big  Sandy.  The 
most  persistent  bed  is  near  the  top  of  the  formation,  just  below  the 
oyster  bed,  but  as  a rule  the  coals  exhibit  the  same  lateral  inconstancy 
as  the  sandstones  and  shales  so  that  they  may  grade  into  clastic  sedi- 
ments within  short  distances. 

The  remarkable  lack  of  lateral  persistence  of  these'  beds  in  the 
original  area  is  clearly  pointed  out  by  Stanton  and  Hatcher(58)  in 
their  excellent  discussion  of  the  geology  of  this  formation.  They  state: 

The  frequency  with  which  the  different  strata  of  sandstones 
and  clays  replace  one  another,  both  laterally  and  vertically,  to- 
gether with  the  great  disturbances  that  have  taken  place  subse- 
quent to  the  deposition  of  the  Judith  River  beds,  renders  it  ex- 
tremely difficult,  if  not  impossible,  to  fix  upon  any  definite  hori- 
zons or  strata  within  the  limits  of  the  fresh-water  series  that  may 
be  followed  and  recognized  with  certainty,  even  in  reasonably  ad- 
jacent sections.  A detailed  section  taken  at  any  point  is  of  little 
value,  since  a similar  section  made  at  a distance  of  only  a mile 
or  two  would  give  a quite  different  sequence  of  the  alternating 
strata  of  sandstones  and  shales. 

Although  similar  conditions  apparently  exist  along  the  Missouri 
and  throughout  the  area  north  of  it,  in  areas  farther  south  the  lithology 
is  more  constant.  In  the  Porcupine  dome  the  formation  is  composed 
of  massive  light-gray  sandstones  at  the  top  and  base  with  interven- 
ing grayish  shales.  In  Musselshell  Valley  it  consists  of  three  fairly 
well-defined  members:  a lower  massive,  cross-bedded,  gray-  to  brown 
sandstone;  a gray  to  buff  clay  shale  with  interbedded  sandstones; 
and  an  upper  series  of  alternating  sandstones  and  shales  with  some 
carbonaceous  shale  and  coal.  The  sandstones  became  markedly  ande- 
sitic toward  the  Crazy  Mountains  as  is  evidenced  by  the  greenish  color 
of  the  fresh  rock  and  the  presence  of  fresh  feldspar  and  quartz  crys- 
tals in  thin  sections.  The  middle  member  contains  considerable  petri- 
fied wood  and  dinosaur  bones,  while  the  osyster-bearing  horizon  is 
present  near  the  top  of  the  uppermost  member (59).  This  three-fold 
division  is  clearly  exhibited  by  the  steeply  dipping  beds  between 
Lavina  and  Broadview.  Coal  seams  are  locally  present  in  this  part 


(58)  Stanton,  T.  W.,  and  Hatcher,  J.  B.,  Geology  and  paleontology  of  the 
Judith  River  beds:  U.  S.  Geol.  Survey  Bull.  257,  p.  34,  1905. 

(59)  Bowen,  C.  F.,  Anticlines  in  a part  of  the  Musselshell  Valley:  U.  S.  Geol. 
Survey  Buil.  691-F,  pp.  191-192,  1918. 


JUDITH  RIVER  FORMATION 


45 


of  the  state  but  as  a rule  they  are  thinner  and  much  less  common 
than  in  the  northern  portion. 

South  of  Yellowstone  Valley  in  Carbon  County  the  Judith  River 
becomes  a part  of  the  thick  series  of  sandstones  that  overlies  the 
Colorado  shale.  It  can  be  readily  traced  from  the  north  to  its  cross- 
ing of  the  river  east  of  Columbus  but  south  of  here  it  is  included  in 
the  1 1 Montana  undivided.  ’ ’ 

On  the  east  flank  of  the  Bighorn  uplift  the  Judith  River  sand- 
stone can  be  traced  to  the  Wyoming  boundary  where  it  is  correlated 
with  the  Parkman  sandstone. 

In  the  northwestern  part  of  the  plains  province  the  Judith  River 
loses  its  identity  through  a change  in  color  and  character  and  grades 
into  the  Two  Medicine  formation (60).  It  can  be  recognized  as  far 
west  as  Milk  Valley  several  miles  above  Havre. 

The  topography  of  the  Judith  River  formation  nearly  everywhere 
is  quite  distinctive.  The  massive,  more  or  less  firm,  sandstones,  in 
flat-lying  beds,  produce  bold  cliffs  and  ledges  which  are  in  conspicu- 
ous contrast  with  the  soft  shales  of  the  overlying  Bearpaw  and  the 
underlying  Claggett.  Extensive  bad  lands  have  been  developed  in 
many  places,  as  in  the  vicinity  of  Havre  and  east  of  Rattlesnake 
P.  0.  Where  the  strata  are  considerably  tilted  the  entire  formation 
has  been  etched  by  erosion  into  a series  of  alternating  hogback  ridges 
and  narrow  depressions.  The  sandstones  commonly  form  prominent 
escarpments  in  the  domes,  which  are  especially  conspicuous  if  the 
underlying  shales  are  exposed.  Pine  examples  of  these  “Keys  to  the 
structure’ ’ are  exhibited  by  the  Porcupine  and  Ingomar  domes,  as 
well  as  by  portions  of  several  other  anticlines. 

Typical  sections  of  the  Judith  River  are  exposed  in  many  deep 
valleys,  among  the  best  of  which  are  those  exhibited  in  the  steep 
slopes  along  the  lower  Judith  River  and  down  Missouri  Valley  for  sev- 
eral miles.  The  exposures  are  especially  fine  on  the  south  side  of  the 
river,  in  the  area  of  sharp  relief  known  as  “Breaks  of  the  Missouri.” 
Excellent  sections  may  also  be  observed  on  the  steep  limbs  of  several 
anticlines  in  Musselshell  Valley,  as  the  south  flank  of  the  Devil’s 
Basin  anticline  and  the  eagt  side  of  the  Broadview  dome.  Many  ex- 
posures occur  in  the  vicinity  of  Havre,  on  the  south  and  west  sides 
of  the  Little  Rocky  Mountains  and  in  the  Bowdoin  dome,  but  none  of 
these  afford  complete  sections. 

A detailed  section  for  the  Lake  Basin  field  about  eleven  miles 
northwest  of  Billings  is  reported  by  Hancock  in  U.  S.  Geological 
Survey  Bulletin  691-D,  page  118,  while  another  a few  miles  southeast 
of  Huntley  is  given  by  him  in  Bulletin  711-G,  page  123. 

The  thickness  of  the  Judith  River  is  fairly  constant  throughout 
the  greater  part  of  the  region,  but  it  thins  rapidly  as  its  eastern  limit 
is  approached.  It  is  estimated  to  be  400  to  425  feet  thick  in  the 

(60)  Stebinger,  Eugene,  The  Montana  Group  of  northwesstern  Montana:  U.  S. 
Geol.  Survey  Prof.  Paper  90-G,  1914. 


46 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


Bowdoin  dome,  about  480  feet  near  Havre,  and  600  feet  in  the  western 
part  of  Musselshell  Valley.  Northwest  of  Billings  it  is  reported  to 
be  nearly  400  feet  thick  and  southeast  of  Huntley  500  feet  thick, 
but  it  decreases  to  125  feet  in  the  northern  part  of  the  Porcupine 
dome,  and  still  farther  east  is  even  thinner. 

The  Judith  River  contains  an  abundance  of  fossils  of  consider- 
able variety,  including  about  fifty  known  species  of  invertebrates,  a 
similar  number  of  vertebrates,  and  an  extensive  flora (61).  Formerly 
all  the  known  forms  were  brackish,  fresh-water,  and  land  types,  but 
marine  fossils  have  been  discovered  recently.  Marine  invertebrates 
are  dominant  on  the  northeast  side  of  the  Bowdoin  dome  (T.  33  N., 
R.  37  E),  where  the  few  fresh-water  shells  (Unios)  are  confined  to 
the  middle  of  the  formation (62).  An  abundance  of  the  marine  sea- 
weed, Halymenites,  and  some  marine  shells  are  present  on  the  north 
side  of  the  Porcupine  dome  (Sec.  8,  T.  12  N.,  R.  38  E)(63).  This  fos- 
sil seaweed  is  also  very  plentiful  several  miles  north  of  Billings,  but 
farther  west  in  Lake  Basin,  brackish-water  mollusca,  leaves,  and  bones 
of  land  animals  are  the  only  fossils  yet  discovered. 

Claggett  formation. — The  Claggett  formation,  or  Claggett 

shale  as  it  may  be  called  in  some  areas,  is  the  thick  mass  of  shale  or 
shale  and  sandstone  that  is  present  between  the  Judith  River  forma- 
tion above  and  the  Eagle  sandstone  below.  The  name  was  given  by 
Stanton  and  Hatcher,  in  their  division  of  the  Montana  group,  to  the 
section  in  the  vicinity  of  old  Fort  Claggett  (now  Judith)  at  the  mouth 
of  Judith  River (64).  The  areal  distribution  of  the  Claggett  is  very 
similar  to  that  of  the  overlying  formation  except  that  in  the  Milk 
River  drainage  it  is  present  only  in  the  Bowdoin  dome,  in  a limited 
area  on  the  northeast  side  of  the  Bearpaw  Mountains,  and  from  the 
vicinity  of  Big  Sandy  northward  beyond  the  Great  Northern  Railway. 
It  is  exposed  in  the  Ingomar  dome  but  not  in  the  McGinnis  Creek 
dome.  It  apparently  continues  below  younger  formations  to  the  east- 
ern border  of  the  state,  and  is  exposed  in  the  Black  Hills  uplift. 

The  Claggett  exhibits  marked  changes  in  lithology  in  crossing  the 
state  from  east  to  west.  In  the  Bowdoin  dome  it  consists  of  a dark 
gray,  clayey  shale  which  forms  a typical  gumbo  soil  and  contains 
numerous  large  limestone  concretions.  Flakes  of  gypsum  which  are 
plentifully  scattered  throughout  the  shale,  give  an  alkaline  character 
to  nearly  all  the  water  from  the  formation.  The  same  .characteristics 


(61)  For  an  excellent  recent  discussion  and  tabulation  of  the  fauna  see  C.  F. 
Bowen,  Stratigraphy  of  the  Montana  group:  U.  S.  Geol.  Survey  Prof.  Paper  90-1 
(1915).  The  flora  and  fauna  have  both  been  described  by  Stanton  and  Hatcher, 
Geology  and  paleontology  of  the  Judith  River  beds:  U.  S.  Geol.  Survey  Bull.  257 
(1905). 

(62)  Collier,  A.  J.,  Geology  of  northwestern  Montana:  U.  S.  Geol.  Survey  Prof. 
Paper  120-B,  pp.  28-29,  1918. 

(63)  Bowen,  C.  F.,  Gradations  from  continental  to  marine  conditions  of  depo- 
sition in  central  Montana  during  the  Eagle  and  Judith  River  epochs:  U.  S.  Geol. 
Survey  Prof.  Paper  125-B,  p.  15,  1919. 

(64)  Stanton,  T.  W.,  and  Hatcher,  J.  B.,  Geology  and  paleontology  of  the 
Judith  River  beds:  U.  S.  Geol.  Survey  Bull.  p.  13,  1905. 


CLAGGETT  formation 


47 


exist  on  the  slopes  of  the  Little  Rocky  Mountains,  and  in  the  upper 
part  of  the  Colorado-Claggett  sequence  in  the  Porcupine  dome.  In  all 
these  areas  the  Claggett  is  so  nearly  identical  with  the  Bearpaw  that 
it  is  recognized  mainly  by  its  stratigraphic  position.  In  some  places 
the  concretions  of  the  older  formation  have  a well-developed  cone-in- 
cone structure  which  is  a feature  that  appears  to  be  seldom  present 
in  the  otherwise  identical  concretions  of  the  Bearpaw. 

In  the  type  area  the  Claggett  is  composed  of  two  facies — a typical 
lower  shale  member  several  hundred  feet  thick,  and  a thinner  upper 
one  of  sandstone  and  shale.  This  two-fold  division  persists  in  variable 
degree  for  a considerable  distance  to  the  north  and  south  of  this 
locality. 

The  gradual  increase  in  .the  proportion  of  sand  from  east  to  west 
is  nowhere  more  clearly  shown  than  in  Musselshell  Valley (65). 

The  Claggett  is  identical  in  appearance  with  the  Bearpaw  in  the 
eastern  part  of  the  valley  but  near  the  western  border  of  Musselshell 
County  two  thin  sandy  zones  appear.  Within  20  miles  to  the  west 
the  sandstones  compose  half  of  the  formation,  while  still  farther 
toward  the  Crazy  Mountains  the  formation  merges  into  the  thick 
series  of  sandstone  and  sandy  shale  which  here  represents  the  Montana 
group  and  the  overlying  formation. 

Southward  toward  Yellowstone  Valley,  and  beyond,  the  sand- 
stones are  more  variable  in  character.  Along  Canyon  Creek  (T.  1 N., 
R.  23  E.),  sandy  shales  'are  interbedded  with  ripple-marked,  thin- 
bedded  sandstones  but  the  latter  gradually  become  less  distinct  as  the 
river  is  approached.  The  sandstones  reappear  southeast  of  Billings 
in  lenticular  beds  which  become  quite  numerous  in  the  valley  of 
Pryor  Creek.  More  persistent,  massive  sandstones  occur  to  the  south- 
east, which  weather  cavernous  and  into  fantastic  forms  similar  to  the 
Judith  River,  but  on  a less  elaborate  scale. 

There  is  common  throughout  the  entire  area  of  the  Claggett,  a 
sandy  transitional  zone  to  the  overlying  Judith  River  formation  and 
to  the  underlying  Eagle  sandstone,  even  where  the  sandy  beds  other- 
wise have  a very  subordinate  development  or  are  entirely  wanting. 
This  makes  it  rather  difficult  in  many  places  to  determine  the  exact 
limits  of  the  formation,  especially  where  sandstones  are  prominent  in 
its  upper  portion.  Where  this  happens  it  has  been  customary  to  in- 
clude these  sandstones  in  the  Claggett,  but  if  all  traces  of  marine 
fossils  are  absent  in  them  it  may  be  advisable  to  call  them  basal 
Judith  River. 

Where  the  Claggett  is  composed  of  shale  its  topography  is  identi- 
cal with  that  of  the  Bearpaw,  broad  lowlands  with  low  rounded  hills 
or  conspicuous  narrow  depressions,  according  to  the  dip  of  the  forma- 
tion. In  areas  of  horizontal  beds,  as  on  the  “ Billings  bench,”  there 
is  a high  frontal  escarpment  of  Eagle  sandstone  with  low  hills  of 

(65)  Bowen,  C.  F.,  Anticlines  in  a part  of  the  Musselshell  Valley,  Mont.:  U.  S. 
Geol.  Survey  Bull.  691-F,  pp.  192-193,  1918.  t 


48 


MONTANA  STATE  BUREAU  OP  MINES  AND  METALLURGY 


PLATE  VI.— EAGLE  SANDSTONE. 

Contact  of  the  massive,  basal  Eagle  sandstone  (Virgelle  sandstone)  with  the  under- 
lying Colorado  shale,  southwest  of  Billings.  The  Virgelle  sandstone 
forms  a common  “rim-rock”  overlooking  valleys  cut 
in  the  softer  Colorado  shales. 


EAGLE  SANDSTONE 


49 


Judith  River  far  in  the  background.  The  more  massive  sandstones 
form  high  cliffs,  and  where  the  formation  is  folded  most  of  them 
give  rise  to  more  or  less  conspicuous  strike  ridges. 

Complete  sections  may  readily  observed  wherever  the  beds  are 
tilted  and  the  underlying  Eagle  is  exposed,  as  on  the  south  flank  of 
the  Devil’s  Basin  anticline,  and  at  several  points  in  Musselshell  Valley. 
Excellent  exposures  are  present  along  the  lower  Judith  River  and  for 
several  miles  in  either  direction  in  the  bluffs  along  the  Missouri. 

Measurements  made  in  several  widely  separated  localities  indicate 
that  the  Claggett  as  a rule  does  not  vary  greatly  in  thickness.  The 
thickest  sections  reported  are  on  the  east  flank  of  the  Little  Rocky 
Mountains  and  on  the  north  side  of  the  Crazy  Mountains  with  750 
feet  and  400  to  800  feet  respectively.  Along  Canyon  Creek,  north- 
west of  Billings,  it  is  567  feet,  near  the  western  border  of  Musselshell 
County  467  feet,  while  in  the  Judith  Basin  north  of  Fullerton  it  is 
620  feet  thick.  In  the  last-named  locality  the  two-fold  division  is  well 
developed, — the  lower  shale  being  about  500  feet  thick  and  the  upper 
sandy  member  120  feet  thick. 

The  Claggett  contains  a fairly  abundant  and  varied  marine  fauna. 
Shells  are  found  in  both  the  shales  and  concretions  but  are  more  com- 
mon in  the  latter.  In  a few  places,  as  in  the  type  area,  the  upper 
sandstones  are  fossiliferous.  Some  characteristic  forms  of  the  shale 
are  Baculites  compressus,  B.  ovatus,  Inoceramus  barabini,  Placenticeras 
whitfieldi,  and  Leda  evansi.  The  fauna  is  very  similar  to  that  of  the 
Bearpaw  shale  but  differs  in  that  it  is  less  diversified  and  fossils  are 
less  numerous. 

Eagle  and  Virgelle  sandstones. — The  basal  formation  of  the 
Montana  group,  in  its  fullest  development,  is  the  Eagle  sandstone. 
This  formation  is  of  considerable  interest  as  a possible  reservoir  of 
oil  and  gas.  The  name  is  derived  from  the  section  at  the  mouth  of 
Eagle  Creek,  a northern  tributary  to  the  Missouri  River  in  the  north- 
eastern part  of  Chouteau  County(66.)  The  lower  part  of  the  Eagle 
has  recently  been  called  the  Virgelle  sandstone,  from  the  exposures 
along  the  Missouri  at  Virgelle,  about  25  miles  below  Fort  Benton (67). 

The  Eagle  sandstone  has  less  extent  than  any  other  formation  of 
the  typical  Montana  group,  being  restricted  to  the  western  and  south- 
ern portions  of  the  plains  province.  North  of  the  Missouri  it  appears 
as  far  east  as  the  Little  Rocky  Mountains  where  thin  encircling  sand- 
stones have  been  provisionally  referred  to  the  Eagle (68).  In  the 
northwestern  part  of  the  region  only  the  massive  basal  sandstone, 
the  Virgelle,  can  be  recognized,  the  remainder  of  the  Eagle,  if  present, 
having  lost  its  identity  and  become  a part  of  the  Two  Medicine  for- 


(66)  Weed,  W.  H.,  U.  S.  Geol.  Survey  Geol.  Atlas,  Fort  Benton  Folio  (No. 
55),  p.  2,  1899. 

(67)  Bowen,  C.  F.,  The  Stratigraphy  of  the  Montana  Group:  U.  S.  Geol.  Survey 

Prof.  Paper  90-1,  p.  97,  1915.  ' 

(68)  Collier,  A.  J.,  Geology  of  northeastern  Montana:  U.  S.  Geol.  Survey  Prof. 
Paper  120-B,  p.  26,  1918. 


50 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


mation.  From  the  type  locality  the  Virgelle  makes  a broad  loop  to 
the  north  as  the  rim  of  the  Sweetgrass  arch  and  swings  as  far  north 
as  Sweetgrass  on  the  Canadian  border.  Each  of  the  three  uplifts  of 
the  Sweetgrass  Hills  is  girdled  with  a narrow  belt  of  the  Virgelle. 
From  Sweetgrass  it  trends  almost  due  south  along  the  western  flank  of 
the  low  arch  to  the  Sun  River  at  the  northwest  corner  of  Cascade 
County,  then  shortly  disappears  beneath  lava  beds  near  Cascade. 
South  of  the  Missouri,  from  Virgelle  the  Eagle  outcrop  is  approxi- 
mately parallel  to  the  Claggett  except  in  the  few  areas  of  the  latter 
where  erosion  has  not  yet  uncovered  the  underlying  sandstones.  The 
formation  cannot  be  recognized  in  the  Porcupine  dome.  On  the  west 
side  of  Bighorn  Basin  the  Eagle  can  be  traced  to  the  Wyoming  line. 
It  is  also  prominently  exposed  in  the  Dean  anticline  and  although 
thin  is  well  exposed  on  the  northeast  flank  of  the  Bighorn  uplift  and 
around  the  northern  end  of  the  Black  Hills  uplift. 

The  Eagle  sandstone  is  quite  generally  composed  of  three  distinct 
divisions;  a lower  very  massive  sandstone,  a middle  zone  of  sandy 
shales,  and  an  upper  division  of  thin  sandstones.  The  basal  member 
retains  its  massive  appearance  with  remarkable  persistence  over  the 
greater  part  of  the  area  occupied  by  the  formation.  It  is  on  account 
of  this  feature  and  the  ready  identification  of  this  division  that  it  is 
commonly  called  the  Virgelle  member.  Even  north  of  the  Missouri 
where  the  upper  portion  of  the  Eagle  can  not  be  identified,  the  Vir- 
gelle maintains  its  typical  appearance.  It  varies  in  color  from  a con- 
spicuous white  in  places  in  the  Missouri  River  Valley  to  gray  and 
light  brown  in  other  localities.  The  upper  part  of  the  Virgelle  north 
of  Teton  River  is  deeply  stained  with  iron  due  to  the  presence  of  thin 
layers  of  magnetite.  Cross-bedding  is  not  uncommon,  and  sandstone 
concretions  of  a rusty  brown  hue  on  the  weathered  surface  are  fairly 
plentiful  in  some  areas.  Weathering  locally  develops  large  caverns, 
and  less  commonly  fantastic  pinnacles  and  other  forms.  In  western 
Musselshell  Valley  the  lower  part  of  the  Eagle  consists  of  thin-bedded 
sandstones,  which  give  place  to  sandy  shales  in  the  Dean  anticline 
many  miles  to  the  south.  Southeast  of  Pryor  Creek,  on  the  Crow 
Indian  Reservation,  the  massive  sandstone  which  is  so  conspicuous 
to  the  northwest  rapidly  grades  into  soft  sandy  shales  that  are  diffi- 
cult to  trace. 

A microscopic  examination  (69)  of  the  Eagle  sandstone  in  Mus- 
selshell Valley  reveals  quartz,  feldspar,  and  black  chert  as  the  prin- 
cipal constituents.  The  sand  grains  here  are  of  medium  size,  and  vary 
form  angular  to  rounded, — about  10  to  15  per  cent  only  having  the 
latter  form.  In  some  other  areas  this  basal  sandstone  is  coarser- 
grained. 

The  middle  member,  while  commonly  composed  of  sandy  shales, 
is  somewhat  variable,  becoming  in  some  places  mainly  thin-bedded 

(69)  Bowen,  C.  F.,  Anticlines  in  the  Musselshell  Valley,  Montana:  U.  S.  Geol. 
Survey  Bull.  691,  p.  195,  1919. 


EAGLE  SANDSTONE 


51 


or  shaly  sandstones.  In  the  vicinity  of  the  Missouri,  and  to  a less 
extent  in  Lake  Basin,  carbonaceous  shales  and  thin,  lenticular  coal 
seams  are  fairly  abundant  at  this  horizon. 

The  upper  division  of  the  Eagle  exhibits  a less  constant  nature 
than  the  others.  Along  Eagle  Creek  it  consists  of  thin  sandstones 
which  partially  pass  into  sandy  shales  south  of  Missouri  River.  In 
some  parts  of  Musselshell  Valley  thick-bedded  sandstones  carrying  an 
abundance  of  large  rusty  sandstone  concretions  predominate.  The 
upper  part  of  the  formation  in  Stillwater  Valley  is  a thick  massive 
sandstone  above  which  workable  coal  beds  are  locally  present.  Minable 
coal  also  occurs  in  the  Eagle  in  the  vicinity  of  Bridger  and  in  the 
Elk  Basin  area(70).  There  are  carbonaceous  layers  and  thin  coal 
seams  in  the  upper  member  in  the  vicinity  of  the  Bearpaw  Moun- 
tains. A unique  feature  in  part  of  Lake  Basin  is  a thin  bed  of 
rounded  black  chert  pebbles  about  an  inch  in  diameter  at  the  top  of 
the  formation.  The  long  gentle  dip  slopes  in  places  are  reported  to  be 
covered  with  them.  Another  local  characteristic  of  the  member  is  the 
presence  of  andesitic  material  in  western  Musselshell  Valley.  The 
andesitic  sandstones  weather  to  a deep  brown  color  and  form  ridges 
as  the  result  of  differential  erosion. 

The  topography  of  the  Eagle  is  very  characteristic.  The  lower 
massive  sandstone  forms  ledges  and  cliffs  25  to  100  feet  high  which 
are  in  striking  contrast  to  the  rolling  surface  of  the  underlying  Colo- 
rado shale.  It  constitutes  the  prominent  rim  rock  of  basins  in  the 
latter  formation.  This  is  excellently  exhibited  in  Yellowstone  Valley 
just  north  of  Billings.  Picturesque  canyons  are  developed  where 
streams  have  cut  through  the  gently  dipping  massive  sandstones. 
Fine  examples  exist  along  Two  Medicine  River  just  above  its  mouth 
and  along  several  small  streams  that  cross  the  escarpment  on  the 
north  side  of  Yellowstone  V^alley.  Where  the  formation  is  steeply 
tilted  differential  erosion  commonly  produces  a narrow  strike  valley 
bordered  by  a pair  of  hogback  ridges. 

The  Eagle  is  commonly  about  250  to  300  feet  thick.  It  is  esti- 
mated to  be  only  100  feet  thick  in  the  Little  Rocky  Mountains  and 
to  have  a similar  minimum  thickness  north  of  the  Crazy  Mountains. 
In  the  Blackfeet  Reservation  the  Virgelle  is  reported  to  be  200  to  225 
feet  thick  while  farther  south  this  increases  to  380  feet.  From  its 
maximum  development  in  this  locality  it  decreases  slightly  into  north- 
ern Fergus  County  then  thins  rapidly  to  the  east,  so  that  it  is  not 
exposed  in  the  Porcupine  dome. 

Fossils  are  generally  scarce  or  lacking  in  the  Eagle.  Leaves  are 
present  in  places  in  the  carbonaceous  shales  or  are  associated  with  thfe 
coals.  In  the  Woman’s  Pocket  anticline,  northwest  of  Lavina,  the 
marine  shell  Cardium  speciosum  is  abundant  near  the  top  of  the  for- 


Washburne,  q h Coal  fields  of  the  northeast  side  of  the  Bighorn  Basin, 
Wyoming,  and  of  Bridger,  Montana:  U.  S.  Geol.  Survey  Bull.  341,  pp.  183-195, 


52 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


mation.  The  same  form  is  sparingly  present  in  the  Big  Elk  dome 
south  of  Two  Dot(71).  Marine  fossils  also  occur  in  the  formation  in 
Carbon  County  where  they  are  more  abundant  in  the  lower  part(72). 
The  Virgelle  is  reported  to  be  barren  in  places  but  in  others  to  con- 
tain a marine  near-shore  fauna. 

Two  Medicine  formation. — The  middle  portion  of  the  Montana 
group  undergoes  a decided  change  in  lithologic  character  as  the  ex- 
treme northwestern  part  of  Central  Montana  is  approached.  In  the 
area  between  Sun  River  and  the  Canadian  boundary,  thence  eastward 
to  Milk  River  Valley,  the  Virgelle  sandstone  and  the  Bearpaw  shale 
are  the  only  divisions  of  the  Montana  group  that  persist  in  their 
typical  aspect.  The  upper  part  of  the  Eagle,  the  Claggett,  and  Judith 
River  here  grade  rapidly  into  a mass  of  light-colored  clays  and  sand- 
stones, mainly  of  continental  origin,  about  2000  feet  thick.  This  de- 
posit is  called  the  Two  Medicine  formation  from  the  typical  and 
complete  section  exposed  on  the  lower  course  of  Two  Medicine  River 
in  southeastern  Glacier  County(73). 

The  character  of  the  formation  is  thus  concisely  described  by 
Stebinger: 

It  is  composed  principally  of  light-gray  to  greenish-gray  clay 
and  clay  shale,  so  rudely  bedded  that  it  is  impossible  to  follow  a 
given  stratum  for  any  great  distance.  In  places  the  beds  of  clay 
are  variegated,  red  and  yellow  strata  appearing.  Thin  nodular 
and  non-persistent  limestone,  apparently  of  fresh-water  origin,  also 
occurs  at  irregular  intervals.  Probably  20  per  cent  of  the  total 
mass  of  the  formation  is  made  up  of  soft  coarse-grained  sandstone 
in  lenticular  beds  which,  even  where  20  to  30  feet  thick,  cannot 
be  traced  more  than  1 or  2 miles.  At  many  localities  these  sand- 
stones show  the  very  irregular  cross-bedding  that  is  characteristic 
of  eolian  deposits.  The  lower  200  feet  of  the  formation  is  more 
sandy  than  the  remainder,  probably  half  of  this  part  consisting 
of  massive  sandstone  in  irregular  beds,  the  thickest  measuring  50 
feet (74). 

The  formation  contains  carbonaceous  shale  at  many  horizons  and 
three  well-defined  coal  beds  occur  in  some  places.  These  coals  are 
mined  at  several  localities. 

The  succession  of  soft  clays  and  more  or  less  resistent  sandstones 
provides  ideal  conditions  for  the  formation  of  badlands,  and  conse- 
quently this  type  of  topography  is  extensively  developed  along  the 
numreous  valleys  of  the  region.  Elsewhere  the  Two  Medicine  is 
characterized  by  a gently  rolling  surface. 


(71)  Bowen,  C.  F.,  Anticlines  in  the  Musselshell  Valley,  Montana:  U.  S.  Geol. 
Survey  Bull.  691-F,  p.  194. 

(72)  Fisher,  C.  A.,  Southern  Extension  of  the  Kootenai  and  Montana  Coal-bear- 
ing formations  in  northern  Montana:  Econ.  Geol.,  vol.  3,  p.  94,  1908. 

(73)  Stebinger,  Eugene,  The  Montana  group  of  northwestern  Montana:  U.  S. 
Geol.  Survey  Prof.  Paper  90-G,  p.  62,  1914. 

(74)  Ibid.,  p.  63. 


LIVINGSTON  FORMATION 


53 


The  fossiliferous  character  of  the  formation  is  well  shown  by  the 
following  description: 

Fossils  are  abundant  in  the  Two  Medicine . formation  and  in- 
clude vertebrate,  plant,  and  mollusk  remains  of  many  species. 
Bone  fragments  of  dinosaurs  of  Judith  River  types,  both  herbiver- 
ous  and  carniverous,  and  also  of  turtles  can  be  found  in  almost 
any  extensive  exposure.  Entire  limb  bones  4 to  5 feet  in  length 
belonging  to  the  larger  dinosaurs  were  found  at  several  localities. 
The  mollusks  are  represented  mostly  by  brackish  and  fresh-water 
forms,  especially  the  latter.  Beds  made  up  almost  exclusively  of 
unios  are  present  at  many  horizons,  in  some  places  closely  asso- 
ciated with  dinosaur  bones.  A single  marine  invasion  of  brief 
duration  while  this  formation  was  being  deposited  is  represented 
by  shells  of  the  Claggett  to  Fox  Hills  near-shore  fauna  found  in 
sandstone  about  200  feet  above  the  base  of  the  formation.  The 
plant  remains  are  mainly  leaf  impressions  and  silicified  wood. 
The  leaves  are  all  of  modern-appearing  conifer  and  broad-leaved 
types.  The  fossil  wood  is  distributed  throughout  the,  formation, 
knots  and  entire  sections  of  compressed  tree  trunks  being  com- 
mon(75). 

Livingston  formation. — A thick  mass  of  tuffaceous  sandstone 
and  shale  constitutes  the  surface  formation  over  an  exten- 
sive area  northwest  of  the  Crazy  Mountains,  between  Shields  River 
and  the  Bridger  Range,  in  Yellowstone  Valley  as  far  east  as  Greycliff, 
and  for  some  distance  south  of  Yellowstone  River.  These  strata  were 
called  the  Livingston  formation  by  Weed(76),  from  exposures  near 
Livingston.  Stone  and  Calvert  in  their  more  recent  studies  of  the 
Livingston  throughout  its  entire  area  have  determined  its  main  litho- 
logic features  and  its  stratigraphic  re!ations(77).  They  have  shown 
too  that  the  formation  does  not  cover  as  broad  a tract  in  the  vicinity 
of  the  Crazy  Mountains  as  is  shown  on  the  early  maps  of  the  region. 
The  data  for  the  following  description  are  taken,  from  their  report. 

The  striking  feature  of  the  formation  is  the  large  proportion  of 
volcanic  material  that  it  contains.  Most  of  the  shales  and  sandstones 
contain  some,  and  many  of  them  a great  deal  of  andesitic  debris.  In 
the  southern  part  of  Stillwater  County  320  feet  of  greenish  to  brown- 
ish tuffaceous  beds  intervene  between  the  Eagle  and  the  Lance.  The 
formation  is  well-exposed  along  Stillwater  River  where  a three-fold 
division  is  recognized:  shale  and  sandstone  625  feet  thick,  volcanic 
agglomerate  2000  feet  thick,  and  shale  and  thin  sandstones  2500  feet 
thick(78).  These  members  have  a similar  thickness  on  Boulder  River 


(75)  Stebinger,  Eugene,  Geology  and  coal  resources  of  Northern  Teton  County, 
Montana:  U.  S.  Geol.  Survey  Bull.  6^1-K,  p.  127,  1916. 

(76)  Weed,  W.  H.,  The  Laramie  and  the  overlying  Livingston  formation  of 
Montana:  U.  S.  Geol.  Survey  Bull.  105,  p.  21,  1893. 

(77)  Stone,  R.  W.,  and  Calvert,  W.  R.,  Stratigraphic  relations  of  the  Livingston 
formation  of  Montana:  Econ.  Geol.,  vol.  5,  pp.  551-557,  652-669,  741-764,  1910. 

(78)  Calvert,  W.  R.,  Geology  of  the  upper  Stillwater  Basin,  Stillwater  and 
Carbon  counties,  Montana:  U.  S.  Geol.  Survey  Bull.  641-G,  p.  201,  1916. 


54 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


to  the  west.  The  agglomerate  is  composed  chiefly  of  andesitic  peb- 
bles and  boulders,  which  rarely  show  signs  of  transportation  by  water. 
It  occurs  in  the  form  of  a great  lense  that  extends  westward  from 
West  Rosebud  Creek  on  the  east  to  Yellowstone  River,  near  Springdale. 

On  the  west  side  of  Shields  Valley  and  along  the  east  flank  of 
the  Bridger  Eange  the  Livingston  maintains  its  highly  andesitic  na- 
ture, the  only  conspicuous  change  being  the  disappearance  of  the 
agglomerate  member.  At  some  places,  however,  strata  containing  much 
andesitic  material  are  interbedded  with  the  underlying  Eagle  and  the 
upper  part  of  the  Colorado.  A number  of  species  of  marine  fossils  of 
probable  Bearpaw  age  were  discovered  well  up  in  the  typical  Living- 
ston at  one  locality  and  elsewhere  Judith  River  forms  occur  at  lower 
horizons. 

As  the  Livingston  formation  is  traced  around  the  north  flank  of 
the  Crazy  Mountains  it  is  observed  to  become  less  and  less  andesitic 
at  certain  horizons,  and  to  assume  gradually  the  lithologic  and  faunal 
characteristics  of  the  Montana  group.  In  other  words,  in  the  upper 
Musselshell  Valley  there  is  a gradual  and  apparently  unmistakable 
interfingering  of  the  typical  sedimentary  series  of  the  central  part  of 
the  state  with  the  typical  Livingston  formation  of  the  Shields  and 
Yellowstone  valleys.  Hence,  it  is  concluded  that  the  Livingstone  for- 
mation is  a peculiar  lithologic  unit  which  in  its  particular  area  cor- 
responds to  the  Montana  group  plus  a part  of  the  overlying  Lance 
formation.  Whether  it  may  be  subdivided  into  these  formations  or 
their  time  equivalents  remains  to  be  determined  by  detailed  strati- 
graphic work. 

Colorado  formation. — Immediately  underlying  the  Eagle  sand- 
stone, or  the  Claggett  shale  where  the  Eagle  is  absent,  is  a thick  body 
of  shales  with  subordinate  sandstones  known  as  the  Colorado  forma- 
tion. This  formation  not  only  appears  at  the  surface  over  a vast  area 
in  Montana,  but  underlies  all  the  territory  occupied  by  younger  for- 
mations. Moreover,  it  underlies  thousands  of  square  miles  of  the 
Great  Plains  of  the  United  States  and  Canada.  The  name  was  first 
applied,  with  its  present  significance,  to  extensive  exposures  in  north- 
western Colorado (79).  In  consequence  of  its  highly  petroliferous  na- 
ture in  Wyoming  and  Alberta  the  Colorado  is  of  considerable  interest 
to  the  oil  prospector  in  this  state. 

The  Colorado  shale  is  one  of  the  most  widespread  formations  of 
the  Montana  Great  Plains,  as  it  is  exposed  over  approximately  9000 
•square  miles,  or  nearly  one-tenth  of  the  whole  plains  province.  The 
largest  area  occurs  north  of  Great  Falls  where  it  is  exposed  by  the 
erosion  of  the  Sweetgrass  arch  throughout  an  area  of  7000  square 
miles.  It  is  brought  to  the  surface  in  belts  of  variable  width  around 
each  of  the  mountain  uplifts  as  well  as  in  most  of  the  anticlines  and 


(79)  White,  C.  A.,  Report  on  the  geology  of  northwestern  Colorado:  U.  S.  Geol. 
and  Geog.  Survey  Terr.,  Tenth  Annual  Report,  1878. 


COLORADO  FORMATION 


55 


domes  of  Musselshell  Valley.  It  is  also  exposed  in  the  Porcupine 
dome  and  in  the  northern  extension  of  the  Black  Hills  uplift. 

The  Colorado  group  of  northwestern  Wyoming  has  been  subdivided 
into  several  formations:  the  Thermopolis  shale  at  the  base,  the  Mowry 
shale,  the  Frontier  formation,  the  Carlile  shale,  and  the  Niobrara 
shale.  These  divisions  have  been  identified  in  Elk  Basin  at  the  Mon- 
tana boundary  and  similar  divisions  are  recorded  in  the  Black  Hills 
uplift  but,  with  the  exception  of  the  Mowry,  have  not  been  positively 
recognized  further  north.  Owing  to  its  peculiar  nature  the  Mowry 
has  been  identified  in  many  of  the  Colorado  sections  in  Montana.  It 
is  rather  probable  that  detailed  stratigraphic  study  of  the  Colorado 
formation  in  this  state  will  result  in  the  recognition  of  some  of  the 
other  divisions  into  which  it  is  separated  in  Wyoming.  On  the  other 
hand  it  is  entirely  probable  that  conditions  of  sedimentation  were 
sufficiently  diverse  over  such  an  extensive  province  that  few,  if  any, 
horizons  can  be  directly  correlated  over  long  distances  unless  they 
are  marked  by  some  unusual  and  persistent  feature,  as  in  the  case  of 
the  Mowry  shale.  Since  the  Colorado  sandstones  exhibit  great  varia- 
tion in  number  and  character  in  the  Wyoming  fields,  it  is  clearly 
inadvisable  to  consider  sandstones  in  a particular  section  in  this  state 
to  be  the  same  as  those  that  occur  in  some  other  section  50  to  100 
miles  distant,  and  thus  expect  them  to  exhibit  the  same  features. 

The  Colorado  everywhere  is  dominantly  a dark  bluish-gray  to 
black,  more  or  less  fissile,  clay  shale.  It  contains  variable  amounts 
of  sandy  shales  and  sandstones,  the  latter  as  a rule  being  more  num- 
erous and  thicker  in  the  lower  part  of  the  formation.  This  is 
especially  true  in  Bighorn  Basin,  Wyoming,  but  even  here  they  are 
very  lenticular.  The  sandstones  appear  to  become  less  abundant  and 
to  be  more  limited  in  vertical  range  as  the  state  is  crossed  toward 
the  north.  In  the  Elk  Basin  field  the  principal  horizons  are  the 
Peay  and  Torchlight  members  of  the  Frontier  formation,  both  of 
which  are  oil-bearing,  while  in  the  Bridger  section  the  Torchlight  is 
the  only  important  sandstone(80).  Well  logs  at  Billings,  southwest 
of  Broadview,  and  southeast  of  Shawmut  show  several  thin  sandstones 
in  the  lower  third  of  the  Colorado  section.  In  the  western  part  of 
Musselshell  Valley  sandstones  again  become  numerous  and  thicker,  one 
sandy  horizon  in  the  Big  Elk  dome  being  sufficiently  prominent  to 
warrant  the  name  Big  Elk  Sandstone (81).  This  member  is  about  1200 
feet  below  the  top  of  the  formation,  and  is  about  250  feet  thick. 
It  occupies  the  approximate  position  of  the  Frontier  of  Wyoming. 
Near  the  Crazy  Mountains  about  200  feet  of  sandstones  are  present 
in  the  lower  third  of  the  Colorado.  The  basal  sandstones  in  the 
vicinity  of  the  Big  Snowy  Mountains  are  thick-bedded  and  weather  to 


(80)  Hares,  C.  J.,  unpublished  data,  quoted  by  Hancock,  E.  T.,  U.  S'.  Geol. 
Survey  Bull.  711,  Plate  XV,  1920. 

(81)  Bowen,  C.  F.,  Anticlines  in  a part  of  the  Musselshell  Valley,  Montana: 
U.  S.  Geol.  Survey  Bull.  691-F,  p.  196,  1918. 


56 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


a rusty  brown  color.  These  11  rusty  beds”  are  an  excellent  guide  in 
drawing  the  lower  boundary  of  the  formation  in  this  area. 

Sandstones,  many  of  which  are  20  to  80  feet  thick,  are  prevalent 
in  the  lower  half  of  this  formation  in  the  northern  part  of  the 
state.  A section  on  the  flanks  of  the  Little  Rocky  Mountains  that 
may  be  considered  representative  for  the  northeastern  area  consists  of 
100,  feet  of  Mowry  shale  at  the  base,  325  feet  of  dark-blue  shale,  60 
feet  of  sandstone  capped  by  a thin  bed  of  fossiliferous  limestone,  and 
875  feet  of  bluish-gray  to  black  shale  with  numerous  limestone  concre- 
tions^). 

In  the  northwestern  part  of  the  plains  the  lower  third  of  the 
Colorado  has  been  designated  the  Blackleaf  sandy  member  from  the 
good  exposure  on  Blackleaf  Creek,  in  northern  Teton  County.  A de- 
tailed section  of  it  is  given  by  Stebinger  in  U.  S.  Geological  Survey 
Bull.  691-E,  page  158.  This  division  is  600  to  700  feet  thick  and 
contains  all  the  conspicuous  sandy  horizons  of  the  Colorado  in  this 
region.  The  sandstones  are  medium  to  coarse-grained,  locally  conglom- 
eratic, and  are  somewhat  lenticular.  Numerous  marine  and  brackish- 
water  shells  have  been  found  in  the  sandy  shales  associated  with 
them. 

The  beds  immediately  overlying  the  Blackleaf  in  the  Sun  River 
district  are  distinctly  petroliferous.  They  “consist  of  compact  black 
bituminous  shale  containing  thin  beds  of  impure  limestone  which  in 
places  is  impregnated  along  the  fractures  with  a soft  tarry 
bitumen(83).  Upon  distillation  the  shales  yield  one  to  two  gallons 
of  oil  to  the  ton.  These  beds  are  about  50  feet  thick,  with  the 
several  thin  limestones  occupying  about  one-quarter  of  the  space. 

The  Mowry  shale,  which,  owing  to  the  abundance  of  fish  remains 
that  it  contains,  is  a possible  source  of  oil,  has  been  identified  at 
several  places  in  Montana.  Where  typically  developed  it  is  readily 
recognized  by  the  great  numbers  of  fish  scales  and  its  peculiar 
weathering  to  a porcelain-like  debris.  This  member  is  reported  from 
the  Little  Rockies  as  constituting  the  basal  100  feet  of  the  Colorado. 
It  is  present  on  the  northeast  flank  of  the  Bearpaw  Mountains  and 
in  the  vicinity  of  Great  Falls  and  Lewistown,  but  has  not  been  recog- 
nized in  the  intermediate  area.  It  apparently  occurs  only  in  the 
eastern  part  of  Musselshell  Valley,  forming  a 12-foot  stratum  about 
680  feet  above  the  base  of  the  Colorado  in  the  Devil’s  Pocket  anti- 
cline and  is  also  well  exposed  in  the  Cat  Creek  anticline.  Near 
Bridger  the  Mowry  is  over  200  feet  thick. 

The  upper  part  of  the  Colorado  nearly  everywhere  consists  of 
characteristic  dark-colored  fissile  shale.  Thin  beds  of  sandstone,  lime- 
stone, and  sandy  shale  are  present  in  places  but  they  are  relatively 


(82)  Collier,  A.  J.,  Geology  of  northeastern  Montana:  U.  S.  Geol.  Survey  Prof. 
Paper  120-B,  p.  26,  1918. 

(83)  Stebinger,  Eugene,  Oil  and  gas  geology  of  the  Birch  Creek-Sun  River 
area  in  northwestern  Montana:  U.  S.  Geol.  Survey  Bull.  691-E,  p.  162,  1918. 


COMANCHE  AN  SYSTEM 


57 


unimportant.  Calcareous  concretions  more  or  less  filled  with  veins  of 
calcite  are  rather  common  in  this  division.  A bed  of  volcanic  ash 
is  a local  feature  on  the  south  side  of  the  Highwood  Mountains,  and 
tuffaceous  material  occurs  near  the  top  of  the  formation  on  the  north 
side  of  the  Crazy  Mountains. 

The  summit  of  the  Colorado  is  generally  quite  distinctly  • marked 
by  a change  from  the  dark  shales  to  the  light-coloredi  massive  sand- 
stone or  sandy  shale  of  the  basal  Eagle,  as  well  as  by  the  conspicuous 
difference  in  topographic  expression.  These  upper,  Colorado  shales  bear 
a rather  close  resemblance  to  the  Claggett  and  Bearpaw  shales  but 
differ  in  that  they  are  somewhat  darker,  bedding  is  much  better 
developed,  and  a typical  gumbo  soil  is  more  rarely  produced. 

Typical  sections  of  the  formation  are  well  exposed  at  several 
places  in  the  state,  particularly  on  the  flanks  of  the  mountain  uplifts, 
as  along  the  northwest  end  of  the  Pryor  mountains.  For  the  details 
of  several  complete  sections  the  reader  is  referred  to  the,  publications 
of  the  U.  S.  Geological  Survey(84). 

The  Colorado  formation  has  a rather  uniform  thickness  through- 
out the  state.  It  is  approximately  1360  feet  thick  in  the  Little 
Rockies  and  in  the  northwestern  part  it  varies  from  1500  to  1900 
feet.  It  is  about  1300  feet  thick  north  of  the  Crazy  Mountains  and 
ranges  from  1500  feet  north  of  the  Judith  Mountains  to  2360  feet 
on  the  south  side  of  the  Big  Snowy  Mountains.  The  greatest  thick- 
ness in  Musselshell  Valley  approximates  the  latter  figure.  A section 
in  the  Elk  Basin  district  nearly  2700  feet  thick  apparently  records 
the  maximum  development  of  the  formation  in  Montana. 

Marine  fossils  are  plentiful  in  the  Colorado  shale.  Fish  remains 
are  exceedingly  numerous  in  the  Mowry  shale  member,  but  occur  also 
at  other  horizons  in  some  localities.  Shells  of  invertebrates,  chiefly 
pelecypods  and  gastropods,  are  not  uncommon  in  most  extensive  sec- 
tions, both  in  the  shale  and  in  the  calcareous  concretions  of  the  upper 
portion.  All  the  fossils  are  characteristic  marine  Cretaceous  forms. 

THE  COMANCHEAN  SYSTEM. 

Kootenai  formation. — The  Kootenai  formation  consists  of  a 
widespread  series  of  shales  and  sandstones  that  underlies  the  Colorado 
shale.  The  type  locality  is  in  southwestern  Alberta,  whence  the  name 
is  derived  from  an  Indian  tribe  that  frequented  the  region(85).  The 
formation  passes  beneath  the  surface  before  the  international  bound- 
ary is  reached  but  reappears  at  several  places  in  the  plains  province. 
North  of  Missouri  River  it  crops  out  only  in  the  Little  Rocky  Moun- 


(84)  Bowen,  C.  F.,  Anticlines  in  a part  of  the  Musselshell  Valley:  Bull.  691-F, 
pp.  196-197,  1918;  Calvert,  W.  R.,  Geology  of  the  Lewistown  coal  field,  Bull.  390, 
p.  30,  1909;  Hancock,  E.  T.,  Bull.  691-D,  PI.  XVII  or  Bull.  711-G,  PI.  XV,  1920. 

(85)  Dawson,  Sir  William,  On  the  Mesozoic  floras  of  the  Rocky  Mountain 
region  of  Canada:  Trans.  Royal  Soc.  Canada,  vol.  3,  Sec.  4,  p.  2,  1885. 


58 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


tains  and  along  the  Rocky  Mountain  front.  The  greatest  surface 
exposure  in  the  state  is  east  and  southeast  of  Great  Falls  where  it 
occupies  about  400  square  miles.  A much  smaller  area  exists  south- 
east of  Lewistown,  and  a belt  of  the  formation  encircles  each  of  the 
mountain  uplifts  in  this  part  of  the  state.  The  only  other  outcrops  in 
the  plains  is  a narrow  belt  around  the  northern  extremities  of  the 
Bighorn  and  Pryor  mountains  and  small  areas  in  the  Devil 's  Basin 
and  Cat  Creek  anticlines.  That  is  underlies  the  younger  formations, 
at  least  in  the  central  part  of  the  plains  province,  is  shown  by  its 
having  been  penetrated  by  deep  wells. 

The  Kootenai  formation  consists  essentially  of  alternating,  vari- 
colored shales  and  light-colored  sandstones.  The  sandstones  are  num- 
erous and  thick  in  the  lower  half  and,  as  a rule,  become  thin  and 
scattered  in  the  upper  portion  although  in  many  places  there  is  a 
massive,  coarse  sandstone  in  the  upper  third  of  the  formation,  in 
which  occurs  the  second  and  third  sands  of  the  Mosby  oil  field.  It 
may  correspond  to  the  Greybull  sandstone  member  of  the  Cloverly 
in  Bighorn  Basin.  The  sandstones  are  commonly  gray  to  brown, 
medium  to  coarse-grained,  in  many  places  gritty  to  coarsely  conglom- 
eratic, and  locally  strongly  cross-bedded.  The  lower  ones  vary  in 
thickness  from  10  to  60  or  more  feet,  and  thus  afford  good  horizons 
for  oil  accumulation  if  other  conditions  are  favorable.  Some  of  the 
sandstones  are  rather  nonpersistent  in  the  central  part  of  the  state, 
but  one  stratum  less  than  100  feet  above  the  base  is  so  persistent  in 
the  vicinity  of  the  Big  Snowy  Mountains  that  it  makes  an  excellent 
horizon  marker.  It  is  as  easy  to  trace  owing  to  the  numerous  pines 
which  grow  upon  it. 

Just  below  this  sandstone  occurs  the  workable  coal  seam  of  the 
Lewistown  and  Great  Falls  fields,  which  in  places  is  six  feet  thick. 
In  other  districts  this  horizon  is  represented  by  a thin  coal  seam  or 
by  carbonaceous  shale. 

Limestone  is  sparingly  present  in  the  Kootenai  and  occurs  gen- 
erally in  the  form  of  nodules  in  more  or  less  definite  zones,  or  as  thin 
lenticular  beds.  It  is  commonly  gray  to  buff,  but  locally  is  purplish. 

The  variegated  shales  are  the  striking  and  distinctive  feature  of 
the  Kootenai  formation.  It  is  so  similar  to  the  underlying  Morrison 
in  this  respect  that  the  two  formations  are  readily  confused,  and 
can  only  be  differentiated  by  detailed  work.  The  Kootenai  shales 
are  dominantly  clayey,  but  are  more  or  less  sandy  in  places.  The 
distinctive  color  is  reddish  to  maroon,  with  bands  of  gray,  blue  and 
green.  The  maroon  shales  are  present  at  several  levels  in  the  forma- 
tion, but  the  bulk  of  them  are  in  the  upper  portion,  immediately 
underlying  the  “rusty  beds' ' that  mark  the  base  of  the  Colorado. 
These  upper  shales  weather  to  soils  of  a deep  maroon  color,  which 
can  be  readily  distinguished  at  great  distances.  The  sharp  change  in 
lithology  at  the  upper  contact  is  very  conspicuous  along  the  east  side 
of  the  Big  Snowy  Mountains,  but  is  commonly  less  evident  elsewhere. 


KOOTENAI  FORMATION 


59 


The  two  formations  appear  to  be  everywhere  conformable,  but  the 
absence  of  the  Dakota  sandstone  indicates  the  existence  of  a marked 
hiatus  at  this  horizon. 

Good  sections  of  the  Kootenai  are  rather  scarce.  A full  section 
may  be  measured  in  several  deep  ravines  on  the  north  and  east 
flanks  of  the  Big  Snowy  Mountains,  on  the  north  slope  of  the  Little 
Belt  Mountains,  and  in  Bridger  Canyon.  A section  at  the  last  locality 
shows  the  following  sequence  (86). 

Feet 

Sandstone  and  shale  interbedded;  sandstone  micaceous,  in  paper- 
thin  beds,  in  places  cross-bedded,  light  buff  to  greenish  yel- 
low, marked  by  great  number  of  worm  burrows  or  tracks; 
shale  light  colored  and  sandy;  at  the  top  are  great  numbers 
of  small  rounded  balls  which  contain  phosphatic  material  and 
are  pseudomorphs  after  marcasite.  This  member  is  ridge- 
forming and  contains  at  the  bottom  the  Greybull  sandstone 


member  - 217 

Shale,  brilliantly  colored,  containing  great  numbers  of  gastroliths 
and  a few  bones.  The  different  colors  give  the  shale  a 
banded  effect  and  are  well  exposed  in  Rainbow  Butte,  just 

north  of  Bridger  Canyon 95 

Conglomerate,  composed  mostly  of  black  chert  pebbles  2 inches 
or  less  in  diameter  containing  Paleozoic  fossils.  Toward  the 


top  the  conglomerate  becomes  sandy  and  contains  fewer  peb- 
bles. The  conglomerate  forms  cliffs  on  each  side  of 
Bridger  Canyon  35 

257 

This  section  is  of  the  Cloverly  formation,  which  is  approximately 
equivalent  to  the  Kootenai. 

A section  on  the  east  flank  of  the  Little  Belt  Mountains  illustrates 
the  common  features  of  the  formation  in  the  central  part  of  the 
state (87). 


Colorado  Shale.  Feet 

Shale,  maroon,  sandy,  with  an  occasional  thin  sandstone  layer 200 

Sandstone,  gray,  weathering  tan,  coarse  grained 8 

Shale,  maroon,  sandy  60 

Sandstone,  gray,  coarse  grained,  weathering  irregularly  and  con- 
taining woody  fragments  25 

Shale,  maroon,  sandy  72 

Sandstone,  gray,  massive,  pebbly 50 

Partly  concealed;  sandstone  members  in  upper  part 42 

Shale,  grayish  brown,  compact  6 

Coal  and  carbonaceous  shale  3 

Concealed,  probably  greenish,  sandy  shale  . 87 

Morrison  formation.  

553 


( 86 ) Measured  by  C.  J.  Hares;  quoted  by  E.  T.  Hancock.  U.  S.  Geol.  Survey 
Bull.  691-D,  p.  110,  1918. 

(87)  Calvert,  W.  R.,  Geology  of  the  Lewistown  coial  field,  Montana:  U.  S.  Geol. 
Survey  Bull.  390,  p.  26,  1909. 


60  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

The  Kootenai  is  about  500  feet  thick  in  Fergus  and  Cascade 
counties,  but  increases  to  825  feet  in  the  Little.  Rocky  Mountains  and 
to  approximately  2000  feet  in  the  northwestern  part  of  Central  Mon- 
tana. It  becomes  even  thicker  in  western  Alberta,  where  it  attains 
a thickness  of  2800  feet.  It  thins  to  the  west  and  south,  being  about 
235  feet  thick  north  of  the  Crazy  Mountains  and  257  feet  thick  in 
Bridger  Canyon.  Farther  south  in  the  Bighorn  Basin  the  Cloverly  is  ; 
only  slightly  more  than  100  feet  thick. 

Fossils  as  a rule  are  scarce  in  the  Kootenai,  and  present  little 
diversity.  The  most  common  ones  are  leaves  in  the  carbonaceous 
strata,  which  are  abundant  in  the  Great  Falls  district.  A few  fresh- 
water shells,  mainly  Unios  and  Gastropods,  occur  in  some  places. 
Reptilian  bones  have  also  been  discovered.  All  the  fossils  indicate 
the  terrestrial  origin  of  the  formation. 

Morrison  formation.- — The  Morrison  . formation  is  a widespread 
sheet  of  fresh-water  deposits  that  extends  from  far  south  of  Morrison, 
Colorado,  the  type  locality(88),  as  far  north  at  least,  as  Central  Mon- 
tana. Wherever  present  it  underlies  the  Kootenai,  to  which  it  bears 
such  a close  resemblance  that  it  is  difficult  to  separate  the  two  forma- 
tions in'  most  places.  It  has  been  identified  only  along  the  north  slopes 
of  the  Little  Belt,  Big  Snowy,  Bighorn  and  Pryor  mountains  in  this  ' 

state,  but  probably  is  buried  by  younger  formations  in  the  intervening 

and  adjacent  territory. 

The  following  description  of  the  formation  along  the  north  flank 
of  the  Big  Snowy  Mountains  will  apply  throughout  the  state(89): 

The  Morrison  formation  consists  of  shales,  sandstones,  and 
argillaceous  limestones,  all  apparently  of  fresh-water  origin.  The 
colors  of  these  beds  are  extremely  variable,  greens  and  pinks  pre- 
dominating, but  they  are  seldom,  if  ever,  brilliant  and  possess  a 
characteristic  soft  tint.  In  lithologic  character  and  in  thickness  i 
the  formation  is  fairly  uniform  throughout  the  field,  the  various  j 

sections  approximating  125  feet.  Argillaceous  members  predom-  | 

mate.  The  shales  are  very  clayey  and  the  limestones  also  appear 
to  contain  a high  percentage  of  silica.  The  limestone  members  are  j 
characteristically  bluish  gray  and  break  into  small  blocks.  The  . 
sandstones  are  usually  brownish  and  granular  in  appearance,  and 
in  them  comminuted  bone  fragments  are  of  fairly  common  occur- 
rence. 

Good  sections  of  the  Morrison  are  available  wherever  sharp  val- 
leys have  been  cut  into  the  underlying  formation.  The  following 
section  illustrates  in  detail  its  character  near  the  east  end  of  the 
Little  Belt  Range(90): 


(88)  Cross,  Whitman,  U.  S.  Geol.  Survey  Geol.  Atlas,  Pike’s  Peak  folio  (No. 
7),  1894. 

(89)  Calvert,  W.  R.,  Geology  of  the  Lewistown  coal  field,  Montana:  U.  S. 
Geol.  Survey  Bull.  390,  pp.  22-23,  1909. 

(90)  Ibid.,  p.  23. 


MORRISON  FORMATION 


61 


Kootenai  Formation.  Feet 

1.  Sandstone,  fine  grained,  tan-colored,  weathering  soft  tan, 

containing  bone  fragments  12 

2.  Shale,  greenish,  becoming  sandy  upward,  with  1-foot 

layer  of  limestone,  greenish  gray,  weathering  russet 
12  feet  from  top;  shale  contains  many  Unio  shells 34 

3.  Limestone,  reddish  brown,  weathering  russet,  containing 

an  abundance  of  clear  calcite  crystals 3 

4.  Shale,  greenish  8 

5.  Limestone  and  variegated  shale;  limestone  is  in  thin  layers, 

reddish  brown,  unchanged  by  weathering,  with  cal- 
cite crystals  as  in  (3) 11 

6.  Limestone,  fine  grained,  compact,  containing  small  green- 

ish particles  resembling  glauconite... 2 

7.  Shale,  variegated,  red  and  pink,  predominating 75 

Ellis  sandstone.  

145 

Another  complete  section  southeast  of  Bridger  shows  the  nature 
of  the  formation  in  the  southern  part  of  the  state(91): 

Feet 

Shale,  light  colored  13 

Shale',  reddish  brown  and  maroon 7 

Shale,  light  sandy  : 16 

Sandstone,  light  colored,  fine  to  medium  grained;  weathers 
yellowish.  In  places  massive  and  locally  in  beds  from 

1 foot  to  1%  feet  thick 26 

Shale,  variegated,  commonly  light  colored.  Has  a thin 
maroon  streak  near  the  base  and  a dark-gray  streak 

near  the  top  .' 26 

Sandstone,  single  bed,  very  argillaceous .-.A % 

Shale,  dark  to  reddish  brown;  weathers  reddish;  exhibits  1 

foot  of  light  shale  near  the  top 10 

Sandstone,  light  colored  5 

Shale,  variegated  from  light  to  reddish  brown 13 

Sandstone,  light  colored 13 

Shale,  maroon;  contains  some  interbedded  sandstone;  weath- 
ers light  to  yellowish  brown 10 

Shale,  dark;  weathers  light.  Greenish,  light  brown  and  drab 

are  common  shades  ..... 10 

1491/2 

The  Morrison  is  a comparatively  thin  formation  in  this  state, 
ranging  from  60  to  120  feet  in  southern  Cascade  County  to  150  feet 
in  Elk  Basin.  It  thickens  to  the  south,  and  is  nearly  600  feet  thick 
along  Shoshone  River  in  northern  Wyoming. 

Fossils  are  very  abundant  in  the  formation  in  many  places  but 
only  a few  have  been  collected  from  the  outcrops  in  this  state.  They 
consist  of  plant  remains,  invertebrates,  and  bones  of  several  verte- 
brates, all  of  which  denote  its  terrestrial  origin.  None  of  them, 


(91)  Emery,  W.  B.,  quoted  by  E.  T.  Hancock,  U.  S.  Geol.  Survey  Bull.  711-G, 


62 


MONTANA  ST4.TE  BUREAU  OF  MINES  AND  METALLURGY 


however,  afford  conclusive  evidence  of  its  precise  position  in  the 
stratigraphic  column,  some  geologists  calling  it  Comanchean(92), 
whereas  others  consider  it  as  Jurassic(93).  It  seems  quite  probable 
that  it  is  largely  transitional  but  is  closely  allied  to  the  Kootenai. 

THE  JURASSIC  SYSTEM. 

Ellis  formation. — The  Ellis  formation  is  the  basal  Mesozoic 
formation  throughout  the  greater  part  of  the  plains  province.  Except 
in  a small  area  in  southern  Carbon  and  Bighorn  counties,  where  the 
Chugwater  formation  (Triassic)  is  present,  it  rests  everywhere  upon 
sediments  of  late  Paleozoic  age.  In  places  it  overlies  the  Madison 
limestone  and  the  Quadrant  formation  with  marked  angular  conform- 
ity, for  example,  in  the  vicinity  of  Stockett,  southeast  of  Great 
Falls (94).  Even  where  no  unconformity  is  apparent  the  absence  of 
strata  that  normally  intervene  between  the  Madison  and  the  Ellis 
indicates  a pronounced  gap,  or  hiatus,  in  the  sedimentary  record. 

The  areal  distribution  of  the  Ellis  is  similar  to  that  of  the  Morri- 
son and  Kootenai  except  that  its  outcrop  is  more  restricted  than 
that  of  the  latter.  It  occurs  in  narrow  belts  on  the  flanks  of  the 
several  mountain  uplifts  and  as  long  narrow  embayments  that  extend 
far  down  some  of  the  narrow  valleys  on  these  slopes.  The  formation 
is  exposed  along  the  western  margin  of  the  plains  in  Teton  County, 
and  surrounds  the  Judith,  Big  Snowy  and  Little  Belt  mountains.  On 
some  of  these  slopes  the  outcrop  varies  in  width  from  a small  fraction 
of  a mile  to  several  miles.  The  Ellis  forms  the  central  area  of 

! 

several  small  domes  in  the  vicinity  of  Lewistown.  It  is  present  on 
the  flanks  of  the  Bighorn  and  Pryor  mountains  where  it  passes  into 
the  Sundance  formation  of  Wyoming.  North  of  Missouri  River  it 
appears  at  the  surface  in  the  Little  Rocky  and  Bearpaw  mountains 
and  in  the  Sweetgrass  Hills.  Its  subsurface  distribution  is  unknown 
but  it  probably  is  present  under  the  greater  part  of  the  plains  in 
this  state.  < 

The  formation  is  composed  of  sandstone,  shale,  and  limestone  in 
variable  proportion.  The  following  section  illustrates  its  character 
in  the  Little  Rocky  Monntains(95) : 

Feet 


Sandstone,  massive,  white,  cross-bedded 50 

Shale,  variegated  50 

Sandstone,  yellowish  and  thinner  bedded , 100 

Shale  with  interbedded  sandstone  and  limestone 100 

Limestone,  thin  bedded,  shaly  and  calcareous  shale 200 


500 


(92)  Mook,  C.  C.,  A study  of  the  Morrison  formation:  Annals  N.  Y.  Acad.  Sci., 
vol.  27,  pp.  39-191,  1916. 

(93)  Schuchert,  Charles,  Bull.  Geol.  Soc.  Am.,  vol.  29,  p.  246,  1918. 

(94)  See  U.  S.  Geol.  Survey  Bull.  356,  Pis.  I and  VI,  1909. 

(95)  Collier,  A.  J.,  Geology  of  northeastern  Montana*  U.  S.  Geol.  Survey  Prof. 
Paper  120-B,  p.  25,  1918. 


63 


PLATE  VII.— ELLIS  FORMATION. 

Fcssiliferous  limestones  exposed  in  a railroad  cut  3 miles  west  of  Forest  Grove.  The 
thicker  beds  are  overlain  by  thin-bedded  calcerous  shales. 


64 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


In  the  Bearpaw  Mountains  it  consists  of  a fine-grained,  dark 
gray,  highly  fossiliferous  limestone  about  200  feet  thick  (96). 

A section  south  of  Great  Falls  in  T.  17  N.,  R.  4 E.  shows  the 
common  features  for  this  region(97): 

Feet 


Sandstone,  gray,  weathering  brown,  thin  bedded 60 

Sandstone,  gray,  conglomeratic,  containing  marine  Jurassic 

fossils  : 29 

Limestone,  dove  colored,  massive;  basal  member  brecciated 

and  containing  Jurassic  fossils 60 


149 

In  western  Teton  County  the  formation  is  composed  mainly  of 
dark  calcareous  shales  with  a few  thin  irregular  beds  of  sandstone  and 
limestone,  ranging  in  thickness  from  240  to  310  feet (98).  In  the 
Lewistown  district  the  Ellis  consists  of  thick,  coarse-grained  to  con- 
glomerate sandstones  which  alternate  with  thin  limestones  and  red 
and  green  shales.  The  sandstones  form  prominent  tan-colored  cliffs 
or  ridges  wherever  well  exposed.  Some  of  the  strata  contain  consid- 
erable gypsum.  The  formation  ranges  in  thickness  here  from  65  feet 
on  the  northeast  slope  of  the  Little  Belt  Mountains  to  440  feet  in 
the  South  Moccasin  Mountains. 

Similar  features  characterize  the  Sundance  formation  along  the 
northeast  flank  of  the  Bighorn  Range,  as  is  shown  by  this  typical 
section(99) : 

Feet. 


Green  to  brown  fossiliferous  sandstones 3 

Green  sandy  shale  ■. 20 

Alternating  layers  of  green  and  gray  sandstones,  fossiliferous  at 

top  25 

Gray  sandy  shale;  red  at  base;  concealed  above,  probably  green....  115 
Light-gray  limestone;  oolite  at  base;  thin -bedded  above;  fossilif- 
erous   — - 1 15 

Gray  massive  fossiliferous  sandstones  6 

Thin-bedded  limestone  . 12 

Gray  sandy  shale  L - - 60 

Massive  gray  sandstone;  very  fossiliferous 10 


266 

The  Ellis  formation  is  nearly  everywhere  rich  in  fossils  at  sev- 
eral horizons,  some  beds  being  almost  wholly  composed  of  shells  and 
shell  fragments.  This  feature  is  especially  exhibited  in  a cut  along 
the  Milwaukee  Railway  about  15  miles  east  of  Lewistown.  The 
forms  are  all  marine  or  brackish-water  invertebrates,  among  which 


(96)  Bowen,  C.  F.,  The  Cleveland  coal  field,  Blaine  County,  Montana:  U.  S. 
Geol.  Survey  Bull.  381,  pp.  51-52,  1909. 

(97)  Fisher,  C.  A.,  Geology  of  the  Great  Falls  coal  field,  Montana:  U.  S.  Geol. 
Survey  Bull.  356,  p.  28,  1909. 

(98)  Stebinger,  Eugene,  Oil  and  gas  geology  of  the  Birch  Creek- Sun  River 
area,  northwestern  Montana:  U.  S.  Geol.  Survey  Bull.  691-E,  p.  155,  1918. 

(99)  Darton,  N.  H.,  Geology  of  the  Bighorn  Mountains:  U.  S.  Geol.  Survey 
Prof.  Paper  51,  p.  45,  1906. 


TRIASSIC  SYSTEM 


C5 


Beleminites  densus,  a cigar-shaped  shell,  and  Gryphaea  calcaola,  an 
oyster-like  form,  are  most  characteristic.  All  the  fossils  indicate  the 
late  Jurassic  age  of  the  Ellis.  It  is  thus  stratigraphically  and  faun- 
ally  the  same  as  the  Sundance  formation  of  the  Bighorn  Mountains. 

THE  TRIASSIC  SYSTEM 

Chugwater  formation. — The  only  rocks  of  Triassic  age  in  the 
plains  province  of  Montana  are  contained  in  the  Chugwater  formation, 
which  extends  northward  from  extensive  exposures  in  Wyoming  as  a 
narrow  belt  around  the  northern  extremities  of  the  Bighorn  and  Pryor 
mountains.  The  name  was  first  applied  to  the  section  on  Chugwater 
Creek,  near  Iron  Mountain,  Wyoming(lOO).  The  formation  is  well 

exposed  in  Bridger  Canyon,  southeast  of  Bridger,  just  south  of  the 

Billings-Codv  highway,  where  it  forms  the  core  of  a small  anticline. 
It  crops  out  far  down  the  long  dip  slope  of  Paleozoics  at  many  other 
places  in  both  mountain  ranges.  Typical  features  are  likewise  ex- 
hibited a few  miles  south  of  Pryor,  on  the  Crow  Indian  Reservation, 
and  in  the  eastern  half  of  T.  6 S.,  R.  24  E.  The  formation  also 

crosses  the  state  line  along  the  east  base  of  the  Beartooih  Range; 

elsewhere  it  is  not  present  in  Montana. 

The  Chugwater  is  aptly  called  the  ‘‘Red  Beds, ” as  it  consists 
mainly  of  bright  to  dark  red  sandstones  and  sandy  to  clayey  shales. 
These  brilliantly  colored  strata  form  conspicuous  cliffs  and  ledges 
wherever  exposed  and  thus  are  an  excellent  horizon  marker.  A fine 
example  of  this  is  the  “red  wall”  in  Bridger  Canyon.  Several  beds 
of  massive  gypsum  from  6 to  50  feet  thick  are  present  in  places.  A 
few  thin  limestones  are  interbedded  with  the  sandstones  and  shales. 

A section  in  the  eastern  part  of  the  Crow  Reservation  gives  a 
thickness  of  652  feet  for  the  formation.  It  becomes  thicker  south  of 
the  state  line,  and  reaches  a maximum  of  1200  feet. 

Fossils  are  very  rare  in  the  Chugwater  and  thus  its  age  is  rather 
uncertain.  Recent  stratigraphic  studies  in  the  eastern  part  of  Bighorn 
Basin  have  led  to  the  conclusion  that  the  true  Chugwater  is  probably 
of  Triassic  age(101). 

CORRELATION  OF  THE  MESOZOIC 

The  succession  and  equivalency  of  the  Mesozoic  formations  in 
various  parts  of  the  Montana  plains  are  shown  by  the  correlation 
chart  on  page  66.  The  overlying  Lance  and  the  underlying  Quadrant 
and  Madison  formations  are  also  included.  Sections  north  of  the 


(100)  Darton,  N.  H.,  Comparison  of  the  stratigraphy  of  the  Black  Hills,  Big- 
horn Mountains,  and  Rocky  Mountain  Front  Range:  Bull.  Geol.  Soc.  Am.,  vol.  15, 
p.  397,  1904. 

(101)  Condit,  D.  D.,  Relation  of  the  Embar  and  Chugwater  formations  in  cen- 
tral Wyoming:  U.  S.  Geol.  Survey  Prof.  Paper  98,  pp.  263-270,  1916. 


Correlation  of  the  Mesozoic  and  Late  Paleozoic  formations  of  the  plains  province  of  Montana  and  adjacent  states. 


66 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


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Mississippian  I Madison  Ls. 'Mad is 


QUADRANT  FORMATION 


67 


Canadian  boundary,  in  northwestern  Wyoming,  and  in  the  northwest- 
ern part  of  the  Black  Hills  are  given  for  a comparison  in-  order  to 
show  the  relation  of  the  formations  in  Montana  to  those  in  neighbor- 
ing states. 

The  section  in  Alberta  is  taken  along  the  western  margin  of  the 
Great  Plains,  in  the  southern  part  of  the  province,  and  is  based  upon 
work  by  the  Canadian  Geological  Survey.  Several  publications  of  the 
United  States  Geological  Survey  supply  the  data  for  the  sections  in 
Montana.  The  Elk  Basin  section  shows  the  formations  for  several 
miles  on  both  sides  of  the  Montana-Wyoming  boundary.  The  forma- 
tions below  the  Colorado  are  exposed  along  the  southwest  slope  of  the 
Pryor  Mountains  and  the  east  base  of  the  Beartooth  Range.  The 
section  in  the  Black  Hills  is  taken  from  the  Aladdin  folio  (No.  128) 
and  exhibits  the  formations  that  are  present  in  southeastern  Montana. 

THE  PALEOZOIC 

Formations  of  Paleozoic  age  crop  out  in  the  plains  province  only 
where  mountain-making  forces  have  greatly  unwarped  the  strata  and 
erosion  has  deeply  dissected  the  uplifts.  Good  sections  are  exposed 
in  several  of  the  Rocky  Mountain  front  ranges  and  the  Little  Belt 
and  Judith  Mountains.  The  later  Paleozoics  also  occupy  the  greater 
part  of  the  Bighorn,  Pryor,  and  Big  Snowy  mountains,  and  a small 
area  in  each  of  the  Sweetgrass  Hills. 

The  only  formations  in  this  group  of  immediate  interest  to  the 
oil  prospector  are  those  of  Carboniferous  age,  mainly  the  Quadrant 
formation,  as  the  older  formations  are  not  oil-bearing  in  the  Great 
Plains  nor  Rocky  Mountains.  In  many  of  the  anticlines  the  Quadrant 
is  too  deeply  buried  to  be  economically  accessible,  but  where  reached 
by  the  drill  it  offers  some  encouragement  for  further  exploration. 
The  lithology  of  some  of  the  older  formations,  however,  is  of  pertinent 
interest  in  its  possible  bearing  upon  the  source  of  the  oil  and  gas  that 
occur  in  younger  formations. 

THE  CARBONIFEROUS  SYSTEM 

Quadrant  formation. — The  Quadrant  formation,  which  receives 
its  name  from  the  section  in  Quadrant  Mountain  in  Yellowstone 
Park(102),  is  the  youngest  Paleozoic  formation  in  this  province.  It 
crops  out  extensively  between  the  prominent  Madison  limestone  and 
the  Ellis  formation  in  several  mountain  uplifts,  but  is  absent  in  some 
localities.  It  is  probably  concealed  over  a broad  area,  but  little  is 
known  of  its  distribution  beneath  the  surface  of  the  plains.  The  best 
exposures  of  the  Quadrant  formation  occur  on  the  lower  slopes  of  the 
Little  Belt  and  Big  Snowy  mountains,  in  the  southern  part  of  the 
Judith  Mountains,  and  to  a less  extent  in  the  Little  Rocky  Moun- 


(102)  Peale,  A.  C.,  U.  S.  Geol.  Survey  Bull.  110,  pp.  39-43,  1893. 


68 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


tains.  The  formation  is  also  present  in  the  various  front  ranges  of 
the  Rocky  Mountains.  The  Amsden  and  Tensleep  formations,  which 
are  approximately  equivalent  to  the  Quadrant  formation,  occupy  a 
similar  position  in  the  Bighorn  and  Pryor  mountains. 

As  described  by  Weed  the  Quadrant  in  the  Little  Belt  Mountains 
consists  of  basal  reddish  sandy  clays  and  sandstone  with  some  gypsum 
in  a few  places,  overlain  by  several  hundred  feet  of  bright  green  and 
gray  shale  with  interbedded  gray  limestones(103).  In  this  area  the 
formation  is  commonly  between  300  and  400  feet  thick,  but  it  is  re- 
ported to  be  1400  feet  thick  on  Judith  River  above  Utica. 

The  following  section  shows  the  character  of  the  formation  at  the 
east  end  of  the  range  (104): 


Jurassic;  red  shale.  Feet 

1.  Limestone,  light  gray,  weathering  almost  white,  fossilif- 

erous  in  upper  portion  55 

2.  Shale,  green,  alternating  with  limestone  members  near 

top;  beds  partly  concealed 105 

3.  Sandstone,  white,  soft,  saccharoidal,  basal  members  alter- 

nating with  limestone  layers,  all  weathering  like 
limestone  U- 40 

4.  Shale,  red,  containing  an  abundance  of  irregular  cherts; 

beds  partly  concealed  225 

Madison  limestone. 


425  , 

The  Quadrant  in  this  area  contains  many  fossils  in  its  upper  , 
strata,  all  of  which  are  marine  invertebrate  shells  of  either  late  Mis-  t 
sissippian  or  early  Pennsylvanian  age. 

Madison  limestone. — The  Madison  limestone  wherever  well 

exposed  is  one  of  the  most  conspicuous  formations  of  the  region.  Like 
the  Quadrant  it  is  exposed  only  in  the  mountain  ranges,  being  present 
in  each  of  the  uplifts  of  the  plains  province  as  well  as  in  the  front 
ranges  of  the  Rocky  Mountains. 

It  consists  of  1000  to  1500  or  more  feet  of  gray  to  bluish-gray, 
thin-bedded  to  very  massive,  fine-grained  limestone  which  contains  ' 
more  or  less  chert  and  numerous  fossils.  In  some  areas  the  basal  por- 
tion is  composed  of  shales  and  shaley  limestone.  The  massive  mem- 
bers everywhere  give  rise  to  a rugged  topography, — narrow  box  can- 
yons and  high  steep  cliffs  and  walls  being  common.  In  some  of  the 
uplifts,  as  in  the  Little  Rocky  Mountains,  it  forms  a striking  en- 
circling girdle  broken  here  and  there  by  picturesque  canyons. 

The  diversified  marine  invertebrate  fauna  of  the  Madison  indi- 
cates its  Mississippian  age. 


(103)  Weed,  W.  H.,  Geology  of  the  Little  Belt  Mountains,  Montana:  U.  S. 
Geol.  Survey,  Twentieth  Ann.  Rept.,  pt.  3,  pp.  294-296,  1899. 

(104)  Calvert,  W.  R.,  Geology  of  the  Lewistown  coal  field,  Montana:  U.  S. 
Geol.  Survey  Bull.  390,  p.  16,  1909. 


DEVONIAN  FORMATIONS 


69 


OLDER  FORMATIONS 

Beneath  the  Madison  limestone  there  is  a thick  series  of  alter- 
nating shales  and  limestones  with  few  interbedded  sandstones  which 
comprises  the  Devonian  and  Cambrian  systems.  Rocks  of  Silurian  and 
Ordovician  age  apparently  are  absent  except  in  the  Bighorn  and 
Pryor  mountains  where  strata  of  the  latter  age  are  present.  These 
earlier  Paleozoic  formation^  are  well-exposed  in  the  mountain  ranges 
in  the  vicinity  of  Lewistown.  Only  the  Devonian  formations,  the 
Jefferson  limestone  and  the  overlying  Three  Forks  shale,  are  of  in- 
terest in  this  report.  In  the  central  part  of  the  state  they  consist 
of  a few  hundred  feet  of  alternating  limestones  and  shales,  which  are 
commonly  light-  to  dark-gray,  brown,  or  black  and  emit  a strongly 
fetid  odor  when  freshly  broken.  Both  the  color  and  odor  are  due  to 
considerable  finely  disseminated  organic  matter.  Fossils,  however,  are 
rarely  present.  Some  of  the  beds  are  more  or  less  sandy,  and  a few 
sandstones  as  well  as  most  of  the  limestones  have  a distinct  saccharoi- 
dal  or  granular  texture. 

Whether  these  beds  are  the  source  of  some  of  the  oil  and  gas  of 
the  plains  province  is  unknown,  but  such  an  origin  is  not  improbable. 
If  this  be  the  case,  the  sub-surface  distribution  of  these  formations 
is  of  great  importance,  but  at  present  this  is  almost  wholly  conjec- 
tural. Since  Devonian  formations  are  exposed  in  all  the  mountain 
ranges,  it  seems  fairly  certain  that  they  underlie  the  intermediate 
areas  and  much  of  the  adjacent  territory.  Thus  they  probably  ex- 
tend far  eastward  beneath  the  younger  formation  of  the  plains,  but 
their  eastern  limit  is  unknown. 


PART  III 


ECONOMIC  GEOLOGY 


BY 

G.  S.  LAMBERT 


COAL 

Although  this  bulletin  is  particularly  concerned  with  the  oil  and 
gas  possibilities  of  Central  and  Eastern  Montana,  the  value  of  the 
coal  resources  of  the  area  justifies  a short  description  of  the  coal 
deposits.  Coal  is  known  to  occur  in  the  Kootenai,  Eagle,  Two  Medi- 
cine, Judith  River,  Lance,  and  Fort  Union  formations,  ranging  in 
age,  therefore,  from  the  Lower  Cretaceous,  or  Comanchean,  to  the 
Tertiary.  In  quality  it  ranges  from  brown,  woody-fibered  lignites 
in  Eastern  Montana  to  sub-bituminous  and  bituminous  coals  nearer  the 
mountain  front. 

Kootenai  coal. — Kootenai  (Comanchean)  coal  is  found  at  a hori- 
zon about  60  feet  above  the  base  of  the  formation  in  the  Great  Falls 
and  Lewistown  areas,  the  former  being  the  more  important.  The  seam 
is  from  3 to  12  feet  in  thickness,  is  characteristically  irregular,  and 
consists  of  alternating  coal,  clay,  and  bone  ash  beds (105).  It  is  a 
medium  grade  bituminous  coal  but  its  value,  especially  in  the  Lewis-  j 
town  area,  is  greatly  diminished  by  the  inclusion  of  a large  amount  , 
of  slate. 

Eagle  coal. — Eagle  (Cretaceous)  coal  is  mined  in  the  Bridger  and 
adjacent  fields,  and  in  the  Livingston,  Trail  Creek,  Electric,  and 
Stillwater  Valley  fields,  all  of  which  are  located  in  the  southwest- 
central  part  of  Montana.  In  northern  and  eastern  Montana,  the  Eagle 
formation  is  relatively  barren,  although  small  seams  of  coal  are  re- 
ported north  of  Black  Butte  in  the  vicinity  of  Deerfield,  Fergus 
County (106).  The  Eagle  coal,  which  is  found  in  the  sandy  beds  over- 
lying  the  massive  Virgelle  sandstone  member,  is  bituminous,  but  the 
seams  are  variable  in  thickness  and  most  of  them  high  in  ash.  Only 

(105)  Fisher,  C.  A.,  Geology  of  the  Great  Falls  coal  field:  U.  S.  Geol.  Survey 
Bull.  No.  356,  pp.  50-51,  1909. 

(106)  Bowen,  C.  F.,  Coal  between  Musselshell  and  Judith,  Montana:  U.  S. 
Geol.  Survey  Bull.  No.  541-H,  p.  45,  1912. 


COALS 


71 


that  coal  which  has  been  crushed  during  deformation  and  converted 
into  a coking  coal,  can  be  profitably  mined. 

Two  Medicine  coal. — Two  Medicine  (Cretaceous)  coal,  correlated 
with  the  Belly  River  coal  of  Canada,  is  mapped  only  in  the  north- 
west central  part  of  the  state,  around  the  Sweetgrass  Hills.  It  occurs 
at  three  horizons,  at  the  base,  250  feet  above  the  base,  and  at  the 
top  of  the  formation.  Elsewhere  there  is  coaly  matter  in  carbon- 
aceous shales  2 to  5 feet  thick(107).  There  is  but  little  production 
of  Two  Medicine  coal  but  it  is  medium  grade  bituminous  and  does 
not  weather  materially  and  hence  is  a fair  fuel  when  mined  clean. 

Judith  River  coal. — The  productive  coal  areas  of  the  Judith  River 
(Cretaceous)  formation,  the  equivalent  of  part  of  the  Two  Medicine 
formation,  are  the  Milk  River,  Cleveland,  Big  Sandy,  and  Judith 
Basin  fields,  the  first  two  being  by  far  the  most  important.  The  most 
extensive  mining  is  at  Havre  in  the  Milk  River  field.  The  Milk  River 
and  Cleveland  fields  are  situated,  respectively,  along  Milk  River,  north 
of  the  Bearpaw  Mountains,  and  at  the  east  end  of  the  Bearpaw 
Mountains.  The  Big  Sandy  field  is  situated  at  the  southwest  end  of 
the  Bearpaw  Mountains  and  the  Judith  Basin  field  lies  about  30-35 
miles  farther  south.  The  coal  occurs  between  15-150  feet  below  the 
top  of  the  formation  in  lenticular  seams  which  vary  in  thickness  from 
a fraction  of  an  inch  to  9 feet (108).  The  coal  is  sub-bituminous  and 
contains  a large  amount  of  impurities.  It  has  a low  heat  value,  high 
moisture  and  high  volatile  content,  and  disintegrates  rapidly,  hence 
is  a poor  railroad  or  shipping  coal,  but  is  a valuable  producer  gas 
coal. 

Lance  coal. — There  is  no  coal  being  mined  from  the  Lance  for- 
mation, as  mapped  by  this  survey,  except  for  local  household  use,  as 
the  formation  contains  only  thin,  unimportant  lignite  seams  and  car- 
bonaceous material. 

Fort  Union  coal. — The  Fort  Union  (Tertiary)  coal  fields  include 
the  well  known  Red  Lodge-Bear  Creek  and  Bull  Mountain  (Roundup) 
coal  fields,  as  well  as  the  extensive  lignite  fields  of  Eastern  Montana. 
These  fields,  if  considered  as  bounded  by  the  Lance-Fort  Union  con- 
tact as  shown  on  the  accompanying  geologic  map,  total  about  30,000 
square  miles  in  area. 

The  Fort  Union  formation  consists  of  alternating  sandstones  and 
shales  with  numerous  lignite  and  sub-bituminous  coal  seams.  It  has, 
however,  been  determined  by  the  U.  S.  Geological  Survey  that  only 
those  seams  which  are  30-36  inches  in  thickness  can  be  profitably 
mined.  Whereas,  a great  many  seams  do  not  attain  this  thickness,  at 

(107)  Stebinger,  Eugene,  Geology  and  coal  resources  of  northern  Teton 
County,  Montana:  U.  S.  Geol.  Survey  Bull.  No.  621-K,  p.  126,  1915. 

(108)  Pepperberg,  L.  S.,  Milk  River  coal  field,  Montana:  U.  S.  Geol.  Survey 
Bull.  No.  381-A,  pp.  82-83,  1908. 


72 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


least  10-15  seams  do.  It  is  reported  that  in  the  Sidney  Lignite  field, 
situated  in  the  extreme  eastern  part  of  the  state,  980  feet  of  Fort 
Union  strata  contains  49  feet  of  lignite  in  seams  varying  in  thick- 
ness from  1 inch  to  21  feet.  The  ratio  of  coal  to  the  entire  measures 
is,  therefore,  1 : 20,  whereas,  the  ratio  in  the  Appalachian  fields  is 
about  1 : 40(109).  Eleven  of  the  lignite  seams  are  considered  economi- 
cally important. 

In  the  Bull  Mountain  field  in  Central  Montana  are  26  coal  seams, 
all  of  which  are  more  than  1 foot  in  thickness.  In  contrast  with  the 
typical  woody-textured  lignites  of  the  more  easterly  Fort  Union  fields, 
the  coal  of  the  Bull  Mountain  and  Bed  Lodge-Bear  Creek  coal  fields 
is  sub-bituminous.  This  is  undoubtedly  due  to  the  metamorphism  of 
the  lignites  during  deformation  of  the  Fort  Union  rocks  of  Central 
Montana.  This  coal  may  be  shipped  without  significant  deterioration 
and  is  good  steaming  coal,  hence  it  has  become  important  both  as 
domestic  fuel  and  for  use  by  the  railroads.  The  mines  in  the  Bull 
Mountain  and  Bed  Lodge-Bear  Creek  fields  are  now  the  principal  coal 
producers  of  Montana,  producing  over  63%  of  all  the  coal  mined  in 
the  state.  The  production  in  the  two  districts  during  1918  was  2^810, 
196  tons (110),  and  from  information  available  at  this  time,  it  appears 
that  the  1919  production  was  equal  to  that  of  1918(111). 

The  utilization  of  the  vast  reserves  of  lignite  in  the  more  eastern 
fields  constitutes  one  of  Montana’s  most  interesting  problems.  Among 
the  economic  possibilities  are  these:  Briquetting  of  the  lignite  to  fur- 
nish domestic  fuel,  burning  of  the  lignite  at  the  place  of  production  to 
generate  electric  power,  and  distilling  of  the  lignite  into  various  com- 
mercial products  such  as  producer  gas  and  coal  tars.  Commercial 
products  resulting  from  the  distillation  of  coal  are  of  increasing  im- 
portance and  although  heretofore  they  have  been  derived  almost  en- 
tirely from  the  by-products  of  coking  plants,  it  is  not  improbable  that, 
in  the  near  future,  they  will  be  obtained  from  lignite  such  as  is  found 
in  Montana.  Among  the  more  important  products  secured  are  creosote 
oil,  light  oils,  benzols,  solvent  naphthas,  and  heavy  tars  and  pitch 
products.  These  furnish  dye  stuffs,  various  chemicals  and  drugs, 
tars  and  pitches  used  in  many  industries,  motor  fuels,  and  raw  mate- 
rials used  in  the  manufacture  of  explosives. 

OIL  AND  GAS 
Development 

The  search  for  oil  and  gas  in  Montana  began  in  1897  when  four 
shallow  wells  were  drilled  in  Carbon  County,  (Section . 32,  T.  6 S.,  B. 
18  E).  The  next  year  a well  was  drilled  in  Blaine  County,  near 


(109)  Stebinger,  Eugene,  Sidney  lignite  field,  Montana:  U.  S.  Geol.  Survey- 
Bull.  No.  471-D,  p.  287,  1912. 

(110)  Mineral  Resources  of  the  U-  S.,  1918,  Part  II,  p.  769. 

(111)  Mineral  Resources  of  the  U.  S.,  1919,  Advance  coal  data. 


OIL  AND  GAS  DEVELOPMENT 


73 


Chinook.  In  1901  wells  Were  drilled  in  Flathead  County,  at  the  west- 
ern edge  of  Glacier  National  Park,  and  in  Beaverhead  County,  ten 
miles  south  of  Dillon.  The  rather  desultory  prospecting  which  fol- 
lowed the  failure  of  these  first  efforts  carried  the  search  into  Teton 
and  Chouteau  counties.  These  first  ventures  lacked  some  of  the  es- 
sentials that  make  for  success,  and  in  no  instance  was  there  any  pro- 
duction of  oil  or  gas. 

Baker-Glendive  (Cedar  Creek)  anticline. — The  first  production  of 
gas  in  Montana  was  from  Dawson  County,  near  Glendive  (T.  15  N., 
E.  55  E.),  when  in  1913  a well  owned  jointly  by  tjie  Consolidated  Oil 
and  Gas  Co.  and  the  Mid-West  Oil  Co.  was  drilled  to  a depth  of  2345 
feet,  and  at  a depth  of  840  feet  gas  was  obtained,  the  estimated  pro- 
duction being  1,000,000  cubic  feet  per  day(112).  The  drill  began  in 
the  Bearpaw  shales  on  the  Cedar  Creek  anticline,  and  probably  went 
through  the  Colorado  formation.  The  production  came  mainly  from 
the  sand  840  feet  deep  and  to  a less  extent  from  two  other  sands  in 
the  same  zone,  which  consists  of  about  30  feet  of  alternating  shales 
and  sands  belonging  to  the  Judith  Eiver  formation. 

Further  development  has  proved  three  productive  districts  on  the 
Cedar  Creek  anticline,  the  Glendive  (Cedar  Creek)  field,  the  Baker 
field  near  Baker,  Montana,  and  the  Cabin  Creek  field  which  is  located 
about  half  way  between  Baker  and  Glendive.  Fourteen  wells  were 
drilled  in  the  Glendive  district,  eight  of  which  were  productive.  The 
gas  is  all  used  in  Glendive  for  domestic  and  industrial  purposes.  Two 
wells  have  been  completed  and  capped  in  the  Cabin  Creek  field,  one 
of  them  having  an  estimated  production  of  1,000,000  cubic  feet  daily. 
There  are  four  productive  wells  in  the  Baker  district  which  supply 
Baker  with  gas  for  domestic  purposes  and  for  the  manufacture  of 
carbon  black,  the  production  of  which  is  estimated  at  450  to  500 
pounds  daily. 

Havre  district. — Shortly  after  the  discovery  of  gas  at  Glendive, 
a large  gas  well  was  drilled  at  Havre,  Montana.  Two  wells  had  been 
drilled  in  1914,  which  produced  a little  gas,  but  in  July,  1915,  a well 
in  the  SEx/4  Section  33,  T.  33  N.,  R.  16  E.,  about  2 miles  northeast 
of  Havre,  assured  commercial  production  by  coming  in  with  an  esti- 
mated flush  production  of  10,000,000  cubic  feet  per  day(113).  This  well 
was  drowmed  shortly  after  by  wTater  from  a rival  well,  but  the  com- 
pletion of  a fourth  well  with  an  initial  production  of  1,000,000  cubic 
feet  per  day,  partially  made  good  the  loss.  This  fourth  well  still 
produces  250,000  cubic  feet  per  day  and  with  500,000  cubic  feet  per 
day  from  the  ninth  well,  completed  in  1921,  furnishes  the  entire  supply 


(112)  U.  S.  Geol.  Survey  Min.  Resources  of  the  U.  S.,  Part  II,  Non-Metals, 
1913,  p.  1454. 

(113)  U.  S.  Geol.  Survey  Min.  Resources  of  the  U.  S.,  Part  II,  Non-Metals, 
1915,  p.  980. 


74  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

of  the  Havre  district.  The  wells  were  begun  in  the  Judith  Eiver 
formation  and  were  drilled  into  the  Eagle  sandstone  from  which  the 
gas  is  derived. 

Sweetgrass  Hills  area. — Prospecting  near  the  Montana-Canadian 
line  was  stimulated  by  the  discovery  of  gas  in  Alberta  and  the  area 
between  the  Sweetgrass  Hills  and  the  International  Boundary,  was 
the  site  of  considerable  activity  in  1915-1916.  The  first  well  drilled, 
the  Montana-Canadian  Well  No.  1,  was  started  in  the  Two  Medicine 
formation,  200-300  feet  above  • the  Eagle  sandstone,  and  at  a depth 
of  1860  feet  in  the  basal  Colorado  sandstone,  a flush  production  of 

gas  estimated  at  4,000,000  cubic  feet  per  day  was  obtained(114).  The 

well  was  capped.  Three  other  wells  were  drilled  from  two  of  which 
only  “shows”  of  gas  and  oil  were  found,  but  from  the  third,  known 
as  No.  4 well,  which  went  to  a depth  of  2085  feet,  an  estimated  flush 
production  of  600,000  cubic  feet  of  gas  per  day  was  obtained  at  1887 
feet,  and  2 barrels  of  oil  per  day  at  1955-7  feet.  The  casings  were 
pulled  from  the  three  wells  drilled  last  and  the  field  was  abandoned, 
but  it  is  understood  that  the  present  season  will  see  further  testing 
of  the  region. 

Elk  Basin. — The  first  productive  oil  field  in  Montana  was  dis- 
covered in  1915  when  the  Elk  Basin  wells  were  drilled.  The  develop- 
ment of  the  district  was  rapid  and  by  the  end  of  1916  the  peak  pro- 
duction was  reached,  ten  producing  wells  having  been  completed  and 
the  limits  of  the  field  determined.  The  immediate  effect  was  to  turn 

attention  to ' the  Montana  extension  of  Bighorn  Basin.  Wells  were 

drilled  in  various  localities,  but  none  were  successful  and  the  period 
from  1916  to  1919  witnessed  a marked  decline  in  prospecting. 

Present  stage  and  development. — The  recent  revival  of  interest  in 
oil  and  gas  began  when  the  well  drilled  by  the  Tri-City  and  Van 
Duzen  Oil  Companies  in  Section  29,  T.  8 N.,  R.  21  E.,  on  the  Woman’s 
Pocket  anticline  went  through  the  red  beds  of  the  Kootenai  formation 
and  found  a little  heavy,  black  oil  in  the  underlying  Quadrant  sands. 
Although  there  was  no  commercial  production,  the  finding  of  oil  was 
the  basis  of  a hope  that  production*  could  be  secured  from  the  Quad- 
rant in  other  places  and. in  November,  1919,  the  Van  Duzen  “Discovery 
Well”  in  Devil’s  Basin  (Sec.  24,  T.  11  N.,  R.  24  E.),  found  showings 
of  oil  in  the  Quadrant.  It  was  not  until  the  spring  of  1920,  however, 
that  commercial  production  of  oil  was  really  assured  from  other  than 
the  Elk  Basin  field.  Prospecting  on  the  anticlines  lying  north  of  the 
Devil ’s  Basin  anticline  resulted  in  the  discovery  of  a high  grade 
paraffin  base  oil  in  the  Mosby  dome.  The  Mosby  structure  is  situated 
on  the  Cat  Creek  anticline,  which  extends  from  Black  Butte  (one  of 
the  Judith  Mountain  laccoliths)  easterly  and  southeasterly  beyond 


(114)  Billings,  Paul,  Personal  communication. 


75 


which  here  dips  northeasterly  rather  steeply. 


76 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


Musselshell  Eiver.  Along  the  crest  of  the  anticline  are  several  up- 
warps  or  domes.  The  largest  upwarp  situated  at  the  east  end  of  the 
anticline  is  itself  further  subdivided  into  three  domes,  called  the  West 
Mosby,  Mosby,  and  East  Mosby  domes. 

The  first  discovery  along  the  Cat  Creek  anticline  was  made  in 
the  Mosby  dome,  but  subsequent  work  has  not  been  so  successful 
there  as  in  the  West  Mosby  dome,  where  there  has  been  a rapid  and 
successful  development.  By  April  1,  1921,  27  wells  had  been  com- 
pleted in  the  West  Mosby  dome  and  from  25  of  them,  including  the 
‘ 1 discovery ; ’ well,  oil  is  being  obtained,  whereas  during  the  same  time 
in  the  Mosby  dome  in  only  two  wells  has  oil  been  found. 

The  Colorado  shales  are  exposed  in  the  Mosby  field  and  oil  occurs 
at  a depth  of  1100  to  1300  feet  in  the  basal  Colorado  and  underlying 
Kootenai  sands.  As  yet  no  oil  sand  has  been  found  on  the  Cat  Creek 
anticline  lower  than  the  Kootenai,  although  a well  has  been  drilled 
part  way  through  the  Quadrant  on  the  upwarp  known  as  the  Kootenai 
dome,  which  lies  about  24  miles  west  of  the  West  Mosby  dome. 

The  wells  in  the  West  Mosby  dome  have  been  brought  in  with 
a uniformly  high  flush  production  (reported  as  high  as  2500  barrels 
per  day)  but  decrease,  rapidly  to  a much  lower  settled  production. 
The  flow  is  held  in  tanks  situated  on  the  producing  properties  which 
in  turn  are  connected  with  pipe  lines  running  to  Winnett,  Montana, 
a branch  terminal  station  on  the  Chicago,  Milwaukee  & St.  Paul  Rail- 
road, whence  the  oil  is  shipped  to  Greybull,  Wyoming,  for  refining. 
A 2-inch  and  a 4-inch  pipe  line  have  been  laid  from  the  field  to 
Winnett. 

The  latest  discovery  of  oil  in  Montana  was  made  in  the  Soap 
Creek  anticline,  28  miles  south  of  Hardin  on  the  Crow  Indian  Reser- 
vation. The  structure  is  a small  parallel  flexure  on  the  northeast 
flank  of  the  Bighorn  Mountain  uplift.  The  Colorado  formation  out- 
crops at  the  surface (115)  and  the  oil  was  found  at  1642  feet  in  the 
Quadrant  sands  (equivalent  to  the  Tensleep  or  Embar).  The  oil  is 
reported  to  be  a heavy,  black  oil,  comparable  to  that  secured  in  the 
Lander,  Wyoming  field,  from  the  Carboniferous  beds.  On  account  of 
the  lack  of  transportation  facilities  there  is  no  production  from  this 
well,  although  it  is  estimated  to  be  capable  of  producing  100  barrels 
per  day. 

Development  work  in  Montana  is  not  confined  to  these  producing 
areas.  Hundreds  of  local  companies  have  been  formed  to  prospect 
for  oil  in  many  localities,  and  many  larger  oil  companies  are  en- 
gaged in  extensive  exploration.  The  whole  of  the  plains  area  of  Mon- 
tana is  receiving  attention  and  the  development  of  the  oil  and  gas 
resources  should  be  rapid. 


(115)  Billingsly,  Paul,  Personal  communication. 


OIL  AND  GAS  DEVELOPMENT 


77 


Production. 

The  amount  and  value  of  gas  and  petroleum  produced  in  Mon- 
tana is  shown  by  the  following  tabulations  which  have  been  made 
as  accurate  as  possible  by  consulting  all  available  data. 

Gas. — There  are  three  productive  gas  fields  in  Montana:  Glen- 

dive, Havre,  and  Baker.  The  production  of  each  is  not  shown  separ- 
ately but  has  been  totaled  to  give  the  yearly  production  from  Mon- 
tana. 


1 9 1 5 1 5,555|  $0.4500| 

1916|  213,315|  ,1821| 

1917|  334,42lj  ,2434| 

1918|  177,039|  ,3510| 

1919|*240,000j  No  data  | 
19201*240,000|  No  data  j 


13 

> 


$ 2,500.00 

38.855.00 

81.406.00 

62.148.00 
*110,000.00 
*100,000.00 


Consumers 

Wells  Drilled 

Wells 

\bandoned 

Domestic 

Industrial 

Dry 

Productive 

1 

| 1| 

2 

727 

61 

9 

1216 

121  2 

3 

1| 

1198 

| 

r - 

1 

1 1 

1 

fcr 

c 


P'3 


1 5 
111 
13 
§ 


*Estimated. 

fThree  poductive  wells  drilled  in  1914. 
|Three  wells  not  utilized, 

§No  data  on  drilling  operations. 
**Complete  data  lacking. 


Petroleum. — Until  1920  the  total  production  of  oil  in  Montana 
came  from  Elk  Basin  but  the  production  from  the  West  Mosby  dome 
now  overshadows  that  from  the  older  field,  totaling  in  1920,  236,832% 
barrels,  at  an  average  price  of  $3.10  per  barrel,  valued  at  $734,180.75. 


Wells  Drilled 

Year 

Bbls. 

Produced 

Ave.  Price 
Per  Bbl. 

Value 

Dry 

Productive 

Abandoned 

Wells 

Wells 

Producing 

Reramrks : 

19 15 1 

o| 1 

$ 

1 o 

1 4 

1 o| 

1 - 

|No  facilities  for  ship’ g oil 

1916 

44,917|  $0.98 

44,019 

1 

1 2 

1 0 

1 6 

|Began  shipping  in  June 

1917| 

1918 

1919 
1910 

99,399|  1.47 

69,323|  1.8l| 

| *84,000|No  di  ta| 

| *336,000|No  data| 

146,272 

125,328 

*170,000 

*1,000,000 

1 

1 

i 

1 

1 





0 

1 

1 1 

1 

1 7 

1 



1 

1 

*Estimated. 


The  price  of  crude  Elk  Basin  oil  at  the  beginning  of  1919  was 
$1.85  and  was  $2.25  at  the  close  of  1919,  but  rose  to  about  an  average 
of  $3.00  during  1920. 


Theoretical  Considerations 

A knowledge  of  the  conditions  controlling  the  accumulation  of  oil 
and  gas  is  essential  to  an  intelligent  exploration  of  new  oil  and  gas 


78  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

fields.  The  essential  conditions  are:  (1)  a source  of  oil  and  gas,  (2) 
a porous  stratum,  known  as  a reservoir  rock  in  which  the  oil  and  gas 
can  accumulate,  (3)  an  impervious  stratum,  cap  rock,  sealing  the 
reservoir  rock,  so  as  to  prevent  the  escape  of  oil  and  gas,  and  (4) 
an  enclosed  structure  into  which  the  oil  and  gas  may  migrate  from 
adjoining  areas  to  form  pools.  Other  factors  or  conditions  may  also 
affect  the  commercial  accumulation  of  oil  and  gas,  such  as:  the  size 
of  the  drainage  area,  the  absence  of  water  in  the  oil  sands,  the  depth 
of  the  oil  sands,  and  the  temperatures  and  pressures  existing  during 
the  distillation  of  the  oil  and  gas  from  their  source.  Following  a dis- 
cussion of  the  conditions  enumerated,  their  application  to  the  oil  and 
gas  possibilities  of  Montana  is  taken  up. 

Source  of  oil  and  gas. — Mineral  oil,  or  petroleum,  and  natural  gas 
are  complex  compounds  of  hydrogen  and  carbon,  containing  various 
impurities  such  as  sulphur,  nitrogenous  substances,  and  oxidation 
products.  They  are  classified  into  series  such  as  the  Methane  or 
paraffin  base  series.  To  each  series  a generalized  formula  can  be 
given,  for  example,  that  of  the  Methane  series,  CnH2n-)-2,  The  series 
begins  with  Methane  gas  (CH4)  and  progresses  according  to  the  gen- 
eralized formula,  through  the  gaseous  and  liquid  bitumens  to  the 
solid(116).  When  found  in  underground  reservoirs,  the  gaseous  bitu- 
mens form  gas  pools  and  the  liquid  bitumens  oil  pools. 

Oil  and  gas  have  their  source  either  in  the  distillation  of  organic 
material  or  in  certain  inorganic  reactions.  Belief  in  the  inorganic 
theory  would  lead  one  to  seek  for  oil  and  gas  in  areas  more  greatly 
deformed  through  mountain  uplift  or  volcanic  activity  rather  than  in 
such  areas  as  are  now,  through  a general  belief  in  the  organic  theory, 
considered  promising. 

There  are  three  organic  theories:  (1)  that  oil  and  gas  is  derived 
from  animal  remains;  (2)  that  it  is  derived  from  vegetal  remains; 
and  (3)  that  it  is  derived  from  both  animal  and  vegetal  remains. 
The  last  theory,  called  the  Engler-Hofer  Dual  theory(117),  is  most 
generally  accepted.  The  attempt  to  prove  that  oil  and  gas  are  derived 
from  coal  on  account  of  the  similarity  between  petroleum  and  natural 
gas  and  the  distillation  products  of  coal,  is  refuted  by  geologic  evidence 
which  shows  that  the  oil  producing  horizons  in  most  fields  are  not  the 
coal  horizons  and  are  not  in  any  way  genetically  connected  with  them. 
Furthermore,  oil  and  gas  are  generally  associated  with  marine  forma- 
tions and  salt  water,  whereas  coal  is  associated  with  continental  depos- 
its and  fresh  or  brackish  water.  The  part  played  by  salt  water  in 
the  origin  of  petroleum  is  uncertain.  Some  authors  hold  that  it  is 
essential  as  a preservative  and  precipitant,  others  hold  that  its  pres- 


(116)  For  details  the  writer  is  referred  to  Clarke,  F.  W.,  Data  on  Geol. -chem- 
istry, U.  S.  Geol.  Survey  Bull.  695.  or  to  various  text  books  on  Oil  Geology  or 
Chemistry. 

(117)  Engler  and  Hofer,  “Das  Erdol.”  Yol.  2,  pp.  59-142,  1909. 


RESERVOIR  AND  CAP  ROCKS 


79 


ence  is  not  necessary  but  only  coincidental.  The  elimination  of  coal 
forming  and  land  plants  as  a source  of  oil  and  the  recognition  of 
the  association  of  oil  and  gas  with  marine  sediments  leads  to  the  con- 
clusion that  plant  and  animal  remains,  which  are  deposited  with 
marine  sediments,  are  the  source  of  oil  and  gas.  These  remains  include 
spores,  sea  weeds,  and  soft  parts  of  animals  that  yield  waxy,  fatty, 
gelatinous,  and  resinous  products (118),  and  are  ordinarily  deposited 
with  muds  to  form  black  shales.  Although  oil  and  gas  may  result 
from  bacterial  action  it  is  not  until  the  black  shales  have  been  heavily 
covered  by  younger  sediments  which,  with  the  covering  of  salt  water 
serve  to  prevent  the  rapid  destruction  of  the  organic  matter  by  oxida- 
tion and  to  retain  the  products  of  decomposition,  that,  through  heat 
and  pressure,  resulting  from  deep  burial  or  deformation,  oil  is  distilled 
from  the  organic  matter  (119).  The  presence  of  petroliferous  rocks 
may  be  detected  at  the  surface  by  the  occurrence  of  oil  or  gas  seeps 
or  asphaltic  residium  or  by  actual  outcrops  of  the  petroliferous  rocks, 
which  may  be  recognized  by  their  color,  odor,  or  by  chemical  analysis. 

Reservoir  rock. — The  formation  of  deposits  of  commercial  import- 
ance requires  the  presence  of  porous  rocks  in  which  the  oil  and  gas 
generated  from  the  organic  matter  can  accumulate.  The  amount  of 
oil  and  gas,  and  the  ease  with  which  it  can  be  secured,  depends 
directly  upon  the  number,  size  and  shape  of  the  pores.  The  most  com- 
mon reservoir  rocks  are  sandstones,  those  having  the  largest  capacity 
consisting  of  loosely  cemented,  medium-sized,  rounded  quartz  grains. 
Other  porous  rocks  in  which  oil  and  gas  may  be  found  are  porous 
limestones,  fractured  shales  and  vesicular  lavas. 

Since  oil  and  gas  migrate  upward,  the  reservoir  rocks  are  found 
above  the  source  of  the  oil  and  gas.  Therefore,  the  ideal  reservoir 
bed  is  situated  above  the  petroliferous  shales,  which  are  the  source 
of  the  oil  and  gas.  However,  where  the  rocks  have  been  folded  into 
anticlines  with  steeply  dipping  limbs,  oil  and  gas  may  migrate  upward 
through  cross  fractures  toward  the  crest  of  the  anticlines,  and  enter 
porous  beds,  which  normally  occur  below  the  petroliferous  shales,  the 
source  of  the  oil,  but  which  along  the  anticlines  have  been  uplifted 
above  the  petroliferous  shales  on  either  side.  Thus,  in  Montana  and 
Wyoming  oil  is  derived  from  the  Kootenai  and  Cloverly  sandstones 
which  are  stratigraphically  lower  than  the  Colorado  shales,  which  are 
probably  the  source  of  the  oil. 

Cap  rock. — A relatively  impervious  bed,  usually  of  shale,  must 
overlie  the  porous,  reservoir  bed  in  order  to  retain  the  oil  and  gas 
in  the  reservoir  rock.  Even  a slight  leak  may  have  completely 


(118)  White,  David,  Late  theories  regarding  the  origin  of  oil:  Bull  Greol.  Soc. 
America,  vol.  28,  p.  778,  1917. 

(119)  White,  David,  Genetic  problems  affecting  search  for  new  oil  regions: 
Bull.  153,  Am.  Inst.  Min.  Eng.,  1919;  and  McCoy,  A.  W.,  Notes  on  the  principles 
of  oil  accumulation:  Journ.  Geol.,  vol.  27,  pp.  252-254,  1919. 


80 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


drained  the  reservoir.  Hence,  where  open  fractures  exist  commercial 
accumulations  of  oil  and  gas  are  unlikely.  On  the  other  hand,  some 
good  fields,  notably  the  Elk  Basin  field  of  Wyoming  and  Montana 
have  been  greatly  broken  by  faults,  which  must  have  been  closed  or 
sealed  by  clay  gouge,  rock  flow,  or  cementation. 

Enclosed  structures. — To  prevent  the  farther  migration  of  the 
oil  and  gas  upward  along  the  contact  of  the  reservoir  rock  with  its 
cap  rock,  it  is  essential  that  the  cap  rock  completely  surround  the 
upper  sides  of  the  reservoir  as  well  as  cap  it,  so  as  to  form  an  en- 
closed reservoir.  Enclosed ‘reservoirs  are  formed  in  several  ways  as  is 
illustrated  by  figures  1 to  6,  plate  IX.  The  various  enclosed  struc- 
tures or  reservoirs  have  been  classified  by  F.  G.  Clapp (120)  as  fol- 
lows: 

Class  I — Where  anticlinal  and  synclinal  structure  exists. 

(a)  Strong  anticlines  standing  alone. 

(b)  Well  defined  anticlines  alternating  with  synclines. 

(c)  Structural  terraces. 

(d)  Local  warpings  on  monoclinal  dip. 

(e)  Accumulations  on  monoclines,  due  to  thinning  out  or  change 

in  texture  of  the  sand. 

(f)  Broad  geanticlinal  folds. 

(g)  Overturned  folds. 

Class  II — Quaquaversal  structures. 

(a)  Anticlinal  bulges,  or  “cross  anticlines.  1 ’ 

(b)  Saline  domes. 

(c)  Volcanic  necks. 

(d)  Perforated  domes. 

CLASS  III — Joint  cracks. 

(a)  Joint  cracks  in  sedimentary  rocks. 

(b)  Joint  cracks  in  crystalline  rocks. 

Class  IV — Sealed  faults. 

Class  V — Oil  sealed  in  by  asphaltic  deposits. 

Class  VI — Contact  of  sedimentaries  with  crystalline  rocks. 

Drainage  area, — As  a reservoir  is  assumed  to  drain  all  the  sur- 
rounding area  which  is  underlain  by  beds  that  slope  upward  to  the 
reservoir,  the  amount  of  oil  and  gas  in  any  reservoir  is  controlled  by 
the  size  of  the  drainage  area.  Hence  it  is  clear  that  other  things 
being  equal  that  oil  field  is  most  productive  which  has  the  largest 
drainage  area. 

Water  in  oil  sands. — It  is  uncertain  what  is  the  cause  of  the 
migration  of  oil  and  gas  from  their  source  to  the  reservoir,  but  it  is 
generally  conceded  to  be  due  to  the  migration  of  water  carrying  oil 
and  gas  with  it,  or  forcing  the  oil  and  gas  ahead  of  it.  The  com- 
pacting of  the  petroliferous  muds  into  shales  may  force  the  water 


(120)  Bacon,  Hamor,  and  others;  Amer.  Pet.  Industry,  p.  48,  McGraw-Hill, 
1916. 


OIL  AND  GAS  STRUCTURES 


81 


Fig  1. — Hypothetical  cross-section 
of  a Volcanic  Neck  in  Mexico,  showing 
the  occurrence  of  petroleum  according 
to  Sub-class  II  (c). 


Fig.  2.  Illustration  of  ideal  anti- 
clinal conditions,  shsowing  the  occur- 
rence of  petroleum  according  to 
Class  I. 


Fig.  3.  Ideal  section  of  a lenticular 
sand,  showing  the  occurrence  of  gas 
and  oil  according  to  Sub-class  I (e). 


fifUr  HAGER 


Fig.  5.  Theoretical  section  normal 
to  a fault  plane,  showing  the  occur- 
rence of  petroleum  according  to  Class 
IV. 


Fig.  4.  Theoretical  section,  show- 
ing the  occurrence  of  petroleum  ac- 
cording to  Class  I.  Note  that  the  low- 
er fold  is  non-productive,  the  oil  hav- 
ing migrated  up  the  slope. 


Fig.  6.  Theoretical  section  of  un- 
conformable  contact  of  Arkose  on 
Granite,  showing  the  occurrence  of 
petroleum  according  to  Class  VI. 


PLATE  IX.— GEOLOGIC  STRUCTURES  FAVORABLE  TO  OIL  AND  GAS 
ACCUMULATION. 


82 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


and  oil  and  gas  into  the  more  porous  beds  that  are  not  compacted 
so  readily  as  the  weaker  muds(121),  or  as  has  been  pointed  out(122) 
water  may  through  its  greater  capillary  attraction  replace  the  oil  and 
gas  in  shales  forcing  the  oil  and  gas  into  more  porous  beds. 

Within  the  porous  beds  of  the  reservoirs  the  mixtures  or  emul- 
sions of  gas,  oil  and  water  are  separated  and  the  various  constituents 
arranged  within  the  reservoir  according  to  their  respective  densities, 
the  gas  on  top,  underlain  by  the  oil,  and  that  in  turn  underlain  by 
water.  Where  the  oil  sands  are  only  partly  saturated  with  water,- 
oil  and  gas  may  be  found  in  the  limbs  of  the  enclosed  structure  and 
in  dry  sands,  as  in  places  in  the  Appalachian  region,  may  be  found 
even  in  the  troughs  of  the  synclines. 

Depth  of  oil  sands. — Where,  within  the  enclosed  structure,  erosion 
has  progressed  to  such  an  extent  that  the  oil  sands  occur  at  the  sur- 
face, the  oil  and  gas  which  may  have  been  in  the  sand  would  have 
escaped.  In  almost  every  oil  district  there  are  usually  monuments,  in 
the  shape  of  non-productive  wells,  where  drilling  began  at  or  below 
the  productive  horizon.  At  several  places  in  Montana,  even  where 
only  the  upper  part  of  the  Kootenai  formation  is  exposed  as  in  the  ’ 
Koontenai,  Devil’s  Basin  and  Shawmut  domes,  no  oil  has  been 
obtained  from  the  Kootenai  sandstones. 

On  the  other  hand,  since  the  profitable  extraction  of  • oil  and  . 
gas  depends  upon  the  cost  or  depth  of  drilling,  the  oil  sands  may  be 
so  deep  as  to  preclude  profitable  development.  Whereas  wells  have 
been  drilled  to  a depth  of  over  7000  feet,  yet  it  is  doubtful  if  \ 
profitable  wells  can  be  drilled  anywhere  at  the  present  time  to 
more  than  5000  feet.  Furthermore,  since  the  per  foot  cost  of  drilling 
increases  rapidly  below  a few  hundred  feet  with  increasing  depth, 
deep  wells  to  be  profitable  must  be  large,  long-lived  producers.  The  ; 
limit  of  profitable  drilling  is  of  course  subject  to  much  variation,  i 
depending  upon  such  conditions  as  labor  costs,  efficiency  of  the  drill,  j 
character  of  the  rocks,  production  and  life  of  the  wells,  and  price  of  \ 
crude  oil.  The  limit  in  Montana  or  even  in  Wyoming  has  not  yet  ( 
been  definitely  determined  but  is  probably  not  much  greater  than  , 
3500  feet. 

Physical  conditions  existing  during  distillation. — It  is  obvious 
that  the  character  and  amount  of  the  oil  and  gas  in  any  region  is 
also  dependent  upon  the  physical  conditions,  temperatures  and  pres- 
sures, existing  during  the  distillation  of  oil  and  gas  from  their  source, 
since  distillation  results  largely  from  heat  and  pressure.  Because  the 
character  of  a coal  is  also  dependent  largely  upon  the  temperatures 
and  pressures  to  which  it  has  been  subject,  passing  under  their  influ- 


(121)  Daly,  M.  R.,  The  disastrophic  theory:  Bull.  Am.  Inst.  Min.  Eng.,  No. 
115,  pp.  1137-1157,  1919. 

(122)  McCoy,  A.  W.,  Notes  on  principles  of  oil  accumulation:  Journ.  Geol.,  vol. 
27,  pp.  252-262,  1919. 


DISTILLATION  OF  OIL  AND  GAS 


83 


ence  from  its  initial  stage  of  peat  through  lignite,  sub-bituminous  and 
bituminous  coals  and  to  the  higher  grade  coals' and  even  to  graphite, 
White (123)  has  suggested  the  use  of  the  character  of  the  coals  in 
any  region  as  an  index  or  gauge  of  the  physical  conditions.  Coals  are 
classified  according  to  the  ratio,  called  the  fuel  ratio,  of  the  amount 
of  fixed  carbon  to  the  amount  of  volatile  matter  they  Contain,  or  by 
the  percentage  of  fixed  carbon  in  pure  ash  and  water-free-coal. 
Thus  lignite  usually  contains  less  than  50  per  cent  fixed  carbon,  sub- 
bituminous  coal  from  50  to  60  per  cent,  bituminous  coal  from  55  to 
75  per  cent,  and  the  higher  grade  coals  more  than  75  per  cent. 

Detailed  study  by  White  as  well  as  by  Fuller(124)  and  Gardner(125) 
in  the  Appalachian  and  Mid-Continent  fields  with  a more  general  study 
of  the  other  oil  fields  of  the  world  has  shown  that  although  fields  of 
heavy  oils  occur,  as  in  the  coastal  plain  of  Texas,  where  the  percentage 
of  fixed  carbon  is  less  than  50  per  cent,  in  the  principal  fields  of 
medium  oils  like  those  of  the  Ohio-Indiana  and  Mid-Continent  fields, 
the  amount  of  fixed  carbon  varies  from  50  to  55  per  cent  and  in  the 
principal  fields  of  light  oils  and  gas  of  the  world,  like  the  Appalachian 
field,  the  amount  of  fixed  carbon  varies  from  55  to  60  per  cent. 

Where  the  amount  of  fixed  carbon  varies  from  60  to  65  per  cent, 

commercial  pools  are  rare,  but  the  oil  is  exceptionally  high  grade  when 
found;  gas  wells  are  common  but  are  usually  isolated.  Where  the 
amount  of  fixed  carbon  exceeds  70  per  cent,  oils,  if  present,  will  be 
“ white  oil”  (approximately  kerosene)  in  pockets  too  small  to  be  of 
commercial  importance  though  gas  pockets  may  exist. 

Although  first  advanced  in  193.>5,  practically  no  exception  to  Dr. 
White ’s  principle  of  the  distribution  of  oil  has  been  discovered. 

Since  the  heat  and  pressure  causing  the  devolatization  of  coals  and 
the  distillation  of  oil  and  gases  results  largely  from  deformation,  in 
greatly  deformed,  mountain  built  regions,  the  carbonization  of  the 
coals  is  usually  above  the  65  to  70  limit,  or  “dead  line.”  Although 
as  White  (126)  points  out,  the  carbonization  ratio  applies  only  to  areas 
in  which  alteration  is  regional,  that  is  caused  by  deformation,  not  con- 
tact metamorphism  resulting  from  the  intrusion  of  igneous  rock  bodies, 
yet  igneous  intrusives  such  as  occur  throughout  the  mountains  of 
Montana,  although  more  local  in  their  effect  bring  about  similar 
changes  to  deformation.  Furthermore,  the  escape  of  hot  waters  or 
solutions  from  the  igneous  intrusions,  usually  fill  the  pores  of  the 
adjoining  rocks  with  mineral  matter  converting  reservoir  rocks  into 


(123)  White,  David,  Some  relations  in  origin  between  coal  and  petroleum: 
Wash.  Acad,  of  Sci.,  vol.  6,  pp.  189-212,  1915. 

(124)  Fuller,  M.  L.,  Relation  of  oil  to  carbon  ratios  of  Pennsylvanian  coa’s 
in  Aorth  Texas:  Econ.  Geology,  vol.  14,  pp.  536-542,  1919,  and  Carbon  ratios  in 
Carboniferous  coals  of  Oklahoma,  and  their  relation  to  petroleum:  Econ.  Geology, 
vol.  15,  pp.  225-235,  1920. 

(125)  Gardner,  J.  H.,  The  Mid-Continent  oil  field:  Bull.  Geol.  Soc.  America, 
vol.  28,  pp.  685-720,  1917. 

(126)  White,  David,  Genetic  problems  affecting  search  for  new  oil  regions: 
Mining  and  Metallurgy,  No.  158,  Sec.  21,  p.  7,  Feb.,  1920. 


84 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


firm,  impervious  rocks  such  as  quartzites,  in  which  no  accumulation 
of  oil  and  gas  can  take  place. 

In  conclusion  it  is  well  to  consider  that  owing  to  the  many 
conflicting  or  compensating  conditions,  many  of  them  imperfectly 
understood,  affecting  the  commercial  accumulation  of  oil  and  gas, 

‘ ‘ it  is  not  surprising  that  some  concentrations  of  oil  and  gas  occur 
where,  from  all  surface  indications  (especially  where  the  productive 
rocks  are  obscured  by  a mantle  of  younger,  unconformable  sediments) 
the  conditions  are  unfavorable,  whereas,  some  areas  that  appear  to 
have  the  most  favorable  . structure  are  barren.  ’ ’(127) 

Possibilities  of  Oil  and  Gas. 

This  chapter  on  the  possibilities  of  oil  and  gas  must  serve  as  a 
guide  in  detailed  work  rather  than  as  a final  report  on  any  area,  as 
the  reconnaissance  nature  of  the  field  work  precludes  detailed  dis- 
cussions. As  already  noted,  the  possibilities  will  be  discussed  by  ap- 
plying the  theoretical  conditions  presented  in  the  previous  section,  to 
Montana. 

Sources  of  oil  and  gas. — The  marine  shales  of  the  Claggett  and 
Bearpaw  formations  are  the  only  rocks  above  the  Colorado  formation 
which  need  to  be  considered  as  sources  of  oil  and  gas  as  the  sedi- 
ments of  the  Eagle,  Judith  River,  Lance,  and  Fort  Union  formations 
were  deposited  under  littoral  or  continental  conditions  and  are  not 
known  to  contain  any  black,  bituminous  shales.  Some  such  shales  do 
occur  in  the  Claggett  and  Bearpaw  formations  and  Hancock(128)  has 
reported  surface  indications  of  oil  and  gas  in  the  vicinity  of  Hardin 
and  in  the  northwest  corner  of  Yellowstone  County.  However,  no 
commercial  amount  has  ever  been  found  and  it  is  doubtful  if  either 
the  Bearpaw  or  Claggett  shales  can  furnish  any  significant  quantity 
of  oil  or  gas.  Furthermore,  to  the  west  the  shales  grade  into  alter- 
nating sandstones  and  shales  typical  of  near  shore  or  litoral  deposits. 

The  source  of  most  of  the  oil  and  gas  produced  in  Wyoming  and 
southern  Alberta  is  generally  conceded  to  be  the  black  shales  of  the 
lower  portion  of  the  Colorado  formation.  The  uninterrupted  continu- 
ation of  the  Colorado  formation  from  Wyoming  through  Montana  into 
Alberta  has  long  been  considered  the  most  favorable  indication  that 
Montana  would  produce  oil.  Recent  drilling  has  shown,  however,  that 
in  places  the  lower  black  shales  are  absent.  Stebinger’s  field 
work(129)  in  the  northwestern  part  of  the  plains  area  has  shown 
some  of  the  Colorado  shales  to  be  petroliferous  to  such  an  extent  that 


(127)  Hancock,  E.  T.,  Geology  and  ol  and  gas  prospects  of  the  Huntley  field, 
Montana:  U.  S.  Geol.  Survey  Bull.  711-G,  p.  146,  1920. 

(128)  Hancock,  E.  T.,  Geology  and  oil  and  gas  prospects  of  the  Huntley  field, 
Montana:  U.  S.  Geol.  Survey  Bull.  711-G,  p.  144,  1920,  and  Geology  and  oil  and 
gas  prospects  of  the  Lake  Basin  field,  Montana:  U.  S.  Geol.  Survey  Bull.  691-D, 
p.  126,  1918. 

(129)  Stebinger,  Eugene,  Oil  and  gas  geology  of  the  Birch  Creek-Sun  River 
area,  northwestern  Montana:  U.  S.  Geol.  Survey  Bull.  691-E,  p.  157  and  pp.  161- 
164,  1918. 


SOURCES  OF  OIL  AND  GAS’ 


85 


they  offer  an  unquestioned  source  for  commercial  quantities  of  petro- 
leum. The  main  petroliferous  horizon  seems  to  be  confined  to  the 
lower  150  feet  of  shales  which  overlie  the  Blackleaf  sandy  member- 
Collier(130)  states  of  the  Mowry  member,  1 ‘ it  seems  almost  certain 
that  the  formation  would  yield  oil  if  properly  sampled  and  tested.” 
These  reports  from  the  northwestern  and  northeastern  parts  of  Central 
and  Eastern  Montana,  in  connection  with  the  fact  that  the  major  pro- 
duction from  Wyoming  and  the  entire  production  from  the  Mosby 
dome  in  Central  Montana  is  from  associated  sands,  indicate  that  the 
Colorado  formation  and  in  particular  the  Mowry  member,  is  the 
important  source  of  oil  and  gas  in  Montana.  In  all  places  the  oil 
is  a high  grade?  light  oil  with  a paraffin  base  and  in  Central  Montana 
consists  mainly  of  gasoline  and  kerosene. 

Since  the  Mesozoic  sediments  below  the  Colorado  formation 
are  predominantly  sands  and  shales  of  continental  and  near  shore 
origin  it  is  doubtful  that  any  petroliferous  beds  competent  to  serve  as 
sources  of  oil  or  gas  will  be  found.  Furthermore  no  oil  or  gas  other 
than  that  which  has  migrated  from  other  sources,  have  been  discov- 
ered in  these  formations. 

Two  possible  sources  of  oil  and  gas  are  found  in  the  Paleozoic  sedi- 
ments. Although  the  more  northerly  exposures  of  the  Quadrant  forma- 
tion in  Central  Montana  do  not  show  a dominately  petroliferous  zone, 
yet  some  black  shales  which  may  have  furnished  oil  and  gas  are  found 
and  the  more  westerly  and  southerly  exposures  are  of  a more  favor- 
able character.  The  phosphatic  black  shale  member  of  the  Quadrant, 
which  contains  the  oil  shales  of  southwestern  Montana  is  reported  to 
thin  to  the  eastward(131)  and  whereas  the  Quadrant  sands  have  not 
yet  furnished  commercial  production  in  Musselshell  Valley,  yet  these 
beds  are  productive  in  the  Soap  Creek  anticline.  Along  Mackenzie 
River  in  Canada,  numerous  seeps  of  light  to  heavy  asphaltic  petro- 
leums are  found  in  the  Devonian  limestones.  To  the  south,  along 
Athabasca  River,  these  beds  are  overlain  by  Dakota  sandstones  which 
are  known  as  “tar  sands”  due  to  their  saturation  with  asphaltic 
bitumens  which  appear  to  have  been  derived  from  the  underlying 
limestones.  Southward,  in  Montana,  the  Devonian  beds  are  exposed 
only  in  the  western  mountainous  area  but  underlie  at  least  a part 
of  the  plains  area.  Peale(132)  describes  them  as  black  magnesian 
limestones  “crowded  with  Devonian  fossils,”  and  shales  which  in 
places  form  carbonaceous  phases  of  sufficient  richness  to  form  an 
impure  coal. 

Reservoir  rocks. — Porous  beds  which  may  serve  as  erservoirs  are 
known  at  various  horizons  in  the  upper  Paleozoic  and  Mesozoic  forma- 


(130)  Collier,  Arthur  J.,  The  Bov.  doin  Dome,  Montana,  a possible  reservoir  of 
oil  or  gas,  U.  S.  Geol.  Survey  Bull.  661-E,  p.  199,  1917. 

(131)  Condit,  D.  Dale,  Oil  shale  in  western  Montana,  southeastern  Idaho,  and 
adjacent  parts  of  Wyoming  and  Utah:  U.  S.  Geol.  Survey  Bull.  711-B,  p.  20,  1919 

(132)  Peale,  A.  C.,  Three  Forks  Folio,  U.  S.  G.  S.,  Folio  24,  1986. 


« 


86  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

tions.  The  oil  that  might  be  generated  in  the  Paleozoic  sediments 

finds  suitable  reservoir  rocks  in  .the  Quadrant  formation,  correlated 
with  the  Tensleep,  Amsden,  and  Embar  formations  in  Wyoming.  The 
most  important  reservoir  rocks  belong  to  the  Comanchean  and  Cretaceous 
series  and  serve  as  collecting  sands  for  oil  and  gas  derived  from  the 
associated  Colorado  shales.  The  present  productive  sands  occur  in  the 
Colorado  and  Kootenai  formations  underlying  the  Colorado  shales,  in 
the  Eagle  sands  overlying  the  Colorado  shales,  and  in  the  Judith  River 
formation  overlying  the  Claggett  shales.  The  Frontier  sands,  from 

which  most  of  the  oil  in  Wyoming  is  obtained,  are  only  locally 

developed  in  Montana  and  have  not  yet  proved  to  be  pro- 

ductive in  Montana  except  in  the  Elk  Basin  dome.  The  basal  Colo- 
rado sandstone  or  ‘ 1 Rusty  Beds  ’ ’ is  the  first  of  the  three  oil  sands  of 
the  Mosby  district,  and  the  first  and  second  Kootenai  sandstones  are 
the  two  lower  sands.  The  production  from  the  West  Mosby  dome  is  al- 
most entirely  from  the  upper  sand,  whereas  the  production  from  the 
Mosby  dome  proper,  or  middle  dome,  is  from  the  middle  sand.  Oil  has 
been  obtained  from  the  lowest  sand  in  the  Ten  Spot  well  on  the  West 
Mosby  dome  near  the  edge  of  the  productive  area.  The  chances  for 
production  from  the  two  lower  sands  in  the  West  Mosby  dome  are 
therefore  favorable. 

The  Eagle  sandstones  are  productive  of  gas  in  the  Havre  district 
but  are  not  known  to  contain  oil.  Since  they  are  separated  from  the 
basal  petroliferous  beds  of  the  Colorado  by  1500  to  2000  feet  of  clay 
shales,  which  are  not  readily  traversed  by  fractures  open  sufficiently 
to  allow  the  migration  of  oil  through  them,  it  is  doubtful  if  the 
Eagle  sandstones  contain  any  significant  amounts  of  oil  anywhere  in 
Montana.  Where  traversed  by  large  faults,  as  in  the  Havre  district, 
gas  can  doubtless  migrate  through  the  Colorado  shales,  and  may  col- 
lect in  the  Eagle  sandstones  in  commercial  quantities. 

The  Judith  River  sandstones  also  contain  commercial  amounts  of 
gas  in  the  Cedar  Creek  anticline,  but  are  still  farther  separated  from 
the  source  of  the  oil  and  gas  than  the  Eagle  sandstones,  and  hence 
are  not  likely  to  contain  oil.  In  fact  it  appears  as  if  the  Judith 
River  sands  are  productive  of  gas  in  the  Cedar  Creek  anticline  because 
the  Eagle  or  other  sands  are  lacking  between  the  Judith  River  sands 
and  the  source  of  the  gas  in  the  basal  Colorado  shales.  It  would  be 
unwise,  therefore,  to  prospect  only  the  Judith  River  sands  in  those 
areas  also  underlain  by  the  Eagle  sands. 

Cap  rocks. — Extensive  thick  beds  of  shale  occur  throughout  the 
sedimentary  series  of  Central  and  Eastern  Montana.  Most  of  the 
shales  are  weak  and  incompetent  and  hence,  will  flow  when  under 
the  weight  of  only  a few  hundred  feet  of  overlying  sediments.  There- 
fore, although  they  may  be  broken  by  faults  in  many  places,  they  may 
still  serve  to  cap  the  underlying  sandstones  effectively. 

Favorable  structures. — With  a minor  exception  in  southwest 
Wyoming,  the  only  structures  which  have  proved  to  be  productive  of 


FAVORABLE  OIL  AND  GAS  STRUCTURES 


87 


oil  in  Montana  or  Wyoming  are  domes  or  enclosed  anticlines,  although 
within  these  structures  the  actual  distribution  of  oil  is  controlled  in 
places  by  faults.  The  uplifts  terminated  on  one  side  by  faults,  to  the 
north  and  south  of  the  Bearpaw  mountains,  contain  gas  but  have  not 
yet  been  proved  to  contain  commercial  amounts  of  oil.  The  major 
structural  features  have  already  been  described(133)  and  are  shown 
and  named  on  the  accompanying  structural  map.  Whereas  the  possi- 
bilities of  oil  and  gas  in  each  of  the  structures  can  not  be  discussed, 
on  account  of  the  lack  of  detailed  knowledge,  yet  the  application  of 
the  facts  and  theoretical  principles  already  given  may  be  considered 
further,  profitably. 

Since,  as  already  described,  the  principal  sands,  the  basal  Colo- 
rado and  Kootenai,  in  which  oil  is  now  found  in  Montana  occur  lower 
in  the  geologic  column  than  the  principal  source  of  the  oil,  the  Mowry 
member  of  the  Colorado,  the  most  favorable  structures  are  those  with 
steep  limbs,  affording  a chance  for  the  oil  to  migrate  upward  through 
cross  fractures  toward  the  crest  of  the  fold  where  the  sands  have 
been  uplifted  above  the  petroliferous  shales.  Even  in  Wyoming  where 
the  Frontier  sands  are  well  developed,  no  large  oil  fields  have  been 
found  except  where  the  dips  exceed,  at  least  10  degrees  in  places. 
In  Montana  the  folds  of  steep  dips  occur  chiefly  in  connection  with 
the  main  Rocky  Mountain  uplift,  the  major  axis  of  deformation  of 
Central  Montana  south  of  the  Little  Belt  mountains,  and  the  synclinal 
area  between  this  axis  and  the  main  mountain  uplift,  the  Big  Snowy 
Mountains  anticlinorium,  and  in  the  north  and  south  of  the  Bearpaw 
Mountains  as  well  as  in  the  Sweetgrass  Hills,  Bearpaw  Mountains,  and 
Little  Rocky  Mountain  uplifts.  In  the  Sweetgrass  arch,  and  west  to 
the  area  of  greatly  folded  and  faulted  rocks  near  the  Lewis  over- 
thrust fault  and  in  Eastern  Montana  the  dips  are  usually  less  than  5 
degrees.  However,  the  western  limb  of  the  Cedar  Creek  anticline  dips 
at  an  average  angle  of  20  degrees.  On  the  Sweetgrass  arch,  and  the 
Porcupine  dome  as  well,  a few  minor  uplifts  or  domes  are  reported, 
and  it  is  possible  that  some  of  them  will  have  sufficiently  steep  dips 
to  be  worth  testing. 

However,  it  must  be  borne  in  mind  that  in  general  where  the 
folds  have  the  steepest  dips  they  are  close  together  and  only  a rela- 
tively few  enclosed  anticlines  and  domes  with  steep  dips  have  a suffi- 
ciently large  drainage  to  have  collected  commercial  amounts  of 
oil  and  gas.  It  is  doubtful  if  any  of  the  folds  within  the  main 
mountain  area,  or  even  close  to  the  main  mountain  front,  have  a 
sufficiently  large  drainage  area,  and  doubtless  this  cause  is  one 
of  the  reasons  for  the  failure  resulting  from  drilling  in  the  Woman’s 
Pocket  and  Shawmut  anticlines,  Big  Coulee-Hailstone  dome  and  the 
domes  on  the  Elk  uplift,  all  situated  along  the  axis  of  major  folding, 
in  Central  Montana  between  the  Bighorn  and  Little  Belt  and  Big 


(133)  See  pages  18-24. 


88 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


Snowy  mountains.  This  element  in  the  problem  should  also  be  given 
careful  consideration  in  the  location  of  test  wells  on  the  faulted 
structures  to  the  north  and  south  of  the  Bearpaw  mountains.  On 
the  other  hand,  the  domes  along  the  north  and  south  margins  of  the 
Big  Snowy  anticlinorium,  on  th§  flanks  of  the  Bighorn  mountains, 
and  in  the  synclinal  area  to  the  west,  and  in  Eastern  Montana 
all  have  large  drainage  areas. 

Virtually  all  of  the  sandstones  of  Central  and  Eastern  Montana 
are  saturated  with  water  throughout  their  entire  extent  and  although 
one  or  two  wells  have  been  driven  into  dry  sands,  yet  the  chances  are 
that  within  nearly  all  the  enclosed  structures  of  Central  and  Eastern 
Montana,  the  sands  contain  sufficient  water  to  have  caused  the 
migration  of  oil  and  gas  from  the  surrounding  drainage  area  to  the 
apex  of  the  structure. 

In  all  of  the  mountain  groups  of  Central  Montana,  with  the  excep- 
tion of  the  western  portion  of  the  Bearpaw,  and  the  Highwood  and 
Crazy  mountains  which  are  largely  volcanic  in  character,  Madison 
limestone  and  older  Paleozoic  rocks  and  even  igneous  rock  cores 
are  exposed.  Hence,  they  cannot  be  considered  favorable  to  the  accum- 
ulation of  oil  and  gas.  Furthermore,  in  some  of  the  otherwise  fairly 
favorable  structures,  such  as  the  Kootenai  and  Devil’s  Basin  domes 
and  the  West  and  Middle  domes  of  the  Shawmut  anticline,  the 
Kootenai  formation  is  exposed  and  drilling  has  failed  to  secure  oil 
from  the  shallow  Kootenai  sands  although  some  oil  has  been  obtained 
from  the  much  more  deeply  buried  Quadrant  sands. 

The  lowest  rocks  exposed  in  the  structures  of  Eastern  Montana, 
and  in  several  of  the  structures  of  Central  Montana,  except  in  the  Por- 
cupine dome  and  in  northern  ' extension  of  the  Black  Hills  uplift  in 
southeastern  Montana,  occur  above  the  Colorado  formation.  There- 
fore, to  test  the  basal  Colorado  and  Kootenai  sands,  the  highest  known 
oil  horizons  in  Montana  except  the  Frontier  sand  in  the  Elk  Basin 
dome,  it  will  be  necessary  to  go  through  the  Colorado  formation 
which  has  a thickness  of  1500  to  2200  feet.  Where  the  Bearpaw 
shales  are  the  lowest  exposed  formation,  as  in  several  of  the  structures 
of  Eastern  Montana,  and  a few  in  Central  Montana,  it  will  be  neces- 
sary to  go  through  the  additional  thickness  of  the  Eagle,  Claggett,  and 
Judith  River  formations  amounting  from  600  to  more  than  1200  feet. 
Throughout  Central  and  Eastern  Montana,  the  base  of  the  Colorado 
formation  is  at  least  2000  feet  below  the  base  of  the  Bearpaw  shale 
and  in  most  places  is  nearly  3000  feet  or  more.  Where  the  Lance 
formation  is  the  lowest  rock  exposed,  the  Bearpaw  shales  must  also 
be  penetrated  so  that  the  depth  to  the  base  of  the  Colorado  will  vary 
from  3000  to  more  than  4000  feet.  Since  it  is  doubtful  • if  oil  can 
be  produced  at  a profit  in  Montana  from  depths  of  more  than  3500 
feet,  drilling  for  oil  in  structures  where  the  Lance  is  the  lowest 
exposed  rock  cannot  be  recommended  at  the  present  time  and  not 
until  further  development  has  proved  the  existence  of  oil  in  neigh- 


FAVORABLE  OIL  AND  GAS  STRUCTURES 


89 


boring  structures  where  the  oil  sands  are  shallower.  Gas,  however, 
may  be  sought  at  shallower  depths,  1500  to  2000  feet  less  in  the 
Eagle  sand,  and  2000  to  2500  feet  less  in  the  Judith  River  sand. 

On  the  accompanying  index  structural  map,  the  lowest  exposed 
formation  is  given  with  the  name  of  the  structure  and  also  four  type 
geologic  sections,  referring  in  particular  to  those  parts  of  the  state 
where  the  corresponding  figures  are  shown.  Thus,  by  the  use  of  the 
data  given,  a rough  estimate  of  the  depth  of  the  various  sands  in  any 
structure  may  be  made. 

There  are  an  insufficient  number  of  analyses  of  coal  from  care- 
fully selected  places  to  determine  accurately  the  physical  conditions 
under  which  oil  and  gas  might  have  been  distilled  in  various  portions 
of  the  state  by  plotting  the  carbon  contents  of  the  pure  coals.  In 
general  the  carbon  content  of  the  lignites  of  Eastern  Montana  is 
slightly  less  than  50  per  cent,  hence,  any  oil  which  may  be  found  in 
Eastern  Montana  will  probably  be  of  a heavy  character.  The  carbon 
content  of  the  sub-bituminous  coals  of  the  western  part  of  Eastern 
Montana  and  the  sub-bituminous  and  bituminous  coals  of  Central 
Montana,  except  close  to  the  mountain  uplifts,  ranges  from  50  to  60 
per  cent  and  hence  represent  ideal  conditions  for  the  distillation  of 
medium  and  high  grade  oils  such  as  have  already  been  found.  Close 
to  the  mountains  and  in  the  eastern  part  of  the  Rocky  Mountains  the 
carbon  content  of  the  bituminous  coals  range  from  60  to  72.5  per 
cent,  although  in  places,  as  in  the  Trail  Creek  field(134),  the  carbon 
content  may  be  as  low  as  53.5  per  cent,  and  hence  the  region  cannot 
be  considered  as  favorable  in  general  to  the  occurrence  of  oil  in  quan- 
tity although  some  high  grade  oil  and  gas  may  be  found.  There  are 
virtually  no  analyses  from  which  to  judge  the  carbon  content  of  coals, 
hence  the  metamorphic  conditions,  existing  well  within  the  mountain 
region,  but  in  most  places  it  would  doubtless  exceed  the  “dead-line” 
of  70  per  cent. 

It  cannot  be  denied  that  the  results  of  drilling  during  1920  and 
the  first  half  of  1921  have  been  disappointing.  Several  structures 
where  apparently  the  surface  indications  have  been  favorable  have 
not  yet  been  proved  to  contain  oil  and  possibly  some  have  been 
definitely  disproved,  and  by  June  1st,  .1921,  only  the  Elk  Basin  dome, 
the  West  and  Middle  Mosby  domes,  and  the  Soap  Creek  dome,  have 
been  proved  to  contain  oil  in  profitable  amounts.  On  the  other 
hand  it  can  be  said  in  all  fairness  that  where  competent  examination 
shows  in  Central  or  Eastern  Montana  an  enclosed  structure  with  steeply 
dipping  limbs,  with  a good  drainage  area,  and  with  Judith  River  or 
lower  Cretaceous  rocks  exposed,  there  is  ample  justification  for  a 
test  well. 


(134)  Calvert,  W.  R.,  The  Livingston  and  Trail  Creek  coal  fields,  Montana; 
U.  S.  Geol.  Survey  Bull.  471-E,  p.  402,  1912. 


INDEX 


A. 

Acknowledgements  9 

Amsden  formation,  correlation  of.... 

66,  68,  86 

Anticlines,  occurrence  of  oil  in. .80,  86 


B. 

Baker,  gas  near  

Battle  Creek  anticline,  location 

of  

Bear  Creek,  coal  at  

Bearpaw  Mountains,  coal  near 

44,  51, 

features  of  

formations  in  38,  43,  46 

igneous  rocks  in... .23,  56,  62,  64, 

location  of  . 

Bearpaw  Shale,  characteristics  of 

38, 

distribution  of  

fossils  in  41,  49, 

origin  of  term  . 

possible  source  of  oil  

similarity  to  Claggett  shales.. 37, 

to  Colorado  shales. 

stratigraphic  relation  of 

35,  37,  38, 

thickness  of  

topographic  expression  of 40, 

Belly  River  formation,  correlation 

Belmont  terrace,  location  of  

Benton  group,  stratigraphic  rela- 
tion of  36, 

Bibliography  10, 

Big  Coulee-Hailstone  dome,  loca- 
tion of  

oil  possibilities  of 

Big  Elk  dome,  location  of 

oil  possibilities  of 

Big  Elk  sandstone,  occurrence  of 


Bighorn  Basin,  oil  development 

in  : 

Bighorn  Mountains  uplift,  forma 
tions  35,  36,  50,  58,  60,  62,  64, 

location  of  ; 

oil  

structure  of  

Bighorn  River,  location  of 

Big  Muddy  Creek  dome,  location 

of  ..... 

Big  Sandy,  coal  near 

Big  Snowy  anticline,  location  of.... 
Big  Snowy  Mountains,  formations 

in 22,  55,  58,  60,  62, 

location  of  

structure  of  21, 

Big  Wall  dome,  location  of 

Billingsly,  Paul,  cited 

Birch  Creek,  anticlines  near 

Black  Butte,  location  of  

Black  Butte  dome,  location  of 

Blacktail  Creek  anticline,  location 

of  

Black  Hills  uplift,  formations  in 

36,  43,  46,  50,  54, 

location  of  

structure  of  


73 

23 

71 

71 

23 
51 
88 
1> 

40 
38 

54 
38 
84 
47 
57 

66 

41 
47 

21 

66 

15 

20 

87 

21 

87 

55 

74 

67 

17 

76 

20 

16 

24 
71 
21 

67 

17 
22 
22 
76 
21 

18 
22 

21 

66 

18 

24 


Blackleaf  sandy  member,  character 


of  56 

Bowdoin  dome,  formations  in. ...43,  46 

location  of  23 

Bowen,  C.  F.,  cited 27,  43,  44, 

46,  47,  49,  50,  52,  55,  57,  64,  70 

Bridger,  coal  near  70 

Bridger  Canyon  geology  of 59,  65 

Broadview  terrace,  location  of 21 

Browns  Coulee  anticline,  location 

of  23 

Brush  Creek  dome,  location  of 22 

Bull  Mountains,  coal  field  of 71 

formation  of  „ 27,  34 

location  of  18 

nature  of  coal  in  72 

Button  Butte  terrace,  location  of....  23 

C. 

Cabin  Creek,  gas  near..... 73 

Calvert,  W.  R.,  cited 22,  29, 

32,  53,  57,  59,  60,  68 

and  Stone,  R.  W.,  cited. ...28,  32,  53 

Carbon  black,  manufacture  of 73 

Carbon  County,  early  oil  develop- 
ment in  72 

Carboniferous,  formations  of 68 

Carbon  ratio  of  coals  in  central 

and  eastern  Montana  89 

in  Trail  Creek  coal  field  89 

relation  to  oil  and  gas  fields 82 

Carlile  shale,  stratigraphic  rela- 
tion of  55,  66 

Castle  Mountains,  location  of 17 

Cat  Creek  anticline,  formation  in 

43,  58 

location  of  22 

oil  development  on  74,  88 

structure  of  22 

Cedar  Creek  anticline,  gas  in. ...73,  86 

location  of  23 

structure  of  24 

Chugwater  formation,  characteris- 
tics of  65 

distribution  of  65,  67 

origin  of  name  65 

thickness  of  65 

Claggett  formation,  characteristics 

of  46,  49,  57 

correlation  of  66 

distribution  of  46 

fossils  in  49 

origin  of  name  46 

possible  source  of  oil  shale 84 

similarity  to  Bearpaw  shale. .37,  47 

similarity  to  Colorado  shale 57 

stratigraphic,  relation  of...35,  37,  66 

thickness  of  49 

topographic  expression  of  47 

Clapp,  F.  G.,  cited 80,  81 

Cleveland,  coal  near  71 

Cloverly  formation,  correlation  of 

.— . - 58,  59 

oil  in  80 

section  in  Pyror  Mountains 59 

thickness  of  60 

Coal,  association  with  oil  and 

gas  78 

occurrence  of  70 


92 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


Coal  Creek  anticline,  location 


of  23 

Colgate  sandstons,  stratigraphic  re- 
lation of  26 

view,  showing  30 

Collier,  A.  J.,  cited  41, 

46,  49,  56,  62,  85 

Colorado  formation,  characteristics 

of  — - * _ i . 55 

distribution  of  54 

fossils  in  ______  57 

gas  in  74 

oil  in  .74,  85,  86 

origin  of  name  54 

Petroliferous  shale  in 56,  84 

similarity  to  Bearpaw  shale 57 

similarity  to  Claggett  shale  57 

source  of  oil  and  gas  . 84 

subdivisions  of  55,  66 

thickness  of  _ 57 

Comachean,  formations  of 35,  57 

Concretions,  occurrence  of  27, 

32,  39,  41,  44,  47,  50,  5> 

Condia,  D.  D.,  cited  65,  85 

Conglomerates,  occurrence  of 


Crazy  Mountains,  formations  in 

27,  34,  35,  44,  47,  51,  53,  57,  60 

igneous  rocks  in  53,  87 

location  of  17 

Cretaceous,  formations  of 35,  57 

Cross,  Whitman,  cited  25,  60 

Cut  Bank  anticline,  location  of 22 

Daisy  Dean  dome,  location  of 21 

Dakota  sandstone,  occurrence  of 

- 36,  66 

petroliferous  charcter  of  85 

Daly,  M.  R.,  cited  . 82 

Darton,  N.  H.,  cited  36,  64,  65 

Dawson,  Sir  William  57 

Dean  anticline,  formations  in 50 

location  of  22 

Deerfield,  Fergus  Co.,  coal  near 71 

Devil’s  Basin  anticline,  formations 

in  44,  45,  47 

location  of  1 22 

oil  development  74 

structure’  of  22 

Devil’s  Basin  dome,  location  of 22 

oil  possibilities  of  88 

Devil’s  Pocket  anticline,  location 

of  23 

Devonian,  bituminous  character  of  85 

formations  of  69 

Domes,  See  anticlines — 

Drainage,  main  features  of 16 

Dry  Creek  dome,  location  of 22 

Dupuyer  anticline,  location  of 22 

E. 

Eagle  sandstone,  characteristics 

of  50 

coal  in  ...50,  70 

distribution  of  49 

fossils  in  51 

gas  in  73 

origin  of  name  49 

thickness  of  51 

topographic  expression  of  51 

view,  showing  48 

Eastern  Montana,  carbon  ratios 

in  89 

oil  possibilities  of  88 

East  Mosby  dome,  location  of--22,  74 
Eldridge,  E.  H.,  cited  37 


Electric  coal  field,  age  of  coal  in 70 


Elevations,  regional  17 

Elk  Basin,  formation  in  38,  54,  61,  66 

location  of  22 

oil  in  74 

view,  showing  frontispiece 

Elk  uplift,  location  of  21 

oil  possibilities  of 87 

Ellis  formation,  characteristics  of..  64 

correlation  of  64  66 

distribution  of  ’ 62 

fossils  in  [ 64 

sections  of  64 

stratigraphic  relation  62 

thickness  of  64 

view,  showing  g3 


Embar  formation,  correlation  of 

„ — ------ : 66, 

Emery,  W.  B.,  cited  

Eocene,  formations  of  


Faults,  influence  on  oil  and  gas  ac- 
cumulation   80,  86 

tortional,  near  Billings  ! 20 

Fernie  shale,  correlation  of  66 

Field  work,  record  of  8 

Fisher,  C.  A.,  cited..._.7.738,’ 51,' Ti]  70 

Five  Mile  dome,  location  of 24 

Flathead  County,  oil  development 

in  - 1 72 

Flat  Willow  anticline,  location  of....  23 

Fort  Union  formation,  age  of 25 

characteristics  of  27 

concertions  in  _• 27 

distribution  of  27 

divisions  of  ’’  28 

fossils  of  ’ 29 

lignite  in  27,  71 

origin  of  name  ’ 26 

stratigraphic  relation  " 27 

thickness  of  28 

topographic  expression  of  28 

Fowler,  George  cited  ; 74 

Fox  Hills  sandstone,  correlation 


Frannie  dome,  location  of  ’ 22 

Frontier  formation,  correlation 

of  ------ 55,  66 

occurrence  of  86 

Fuller,  M.  L.,  cited  83  • 

Fuson  shale,  correlation  of  66 

G. 

Gardner,  J.  H.,  cited  83 

Gas,  association  with  coal 78 

with  faults  : 80,  86 

with  salt  water  78 

nature  of  78 

occurrence  near  Glendive  73 

near  Havre  73 

near  Swetgrass  Hills  74 
plate,  illustrating....  81 

origin  of  78 

production  of  77 

theories  of  acumulation  of 78 

Geology,  regional  18,  24 

Gibson  dome,  location  of  21 

Glacial  drift,  distribution  of 18 

Glendive,  gas  near  73 

Graneros  shale,  correlation  of 60 

Great  Falls,  coal  near  70 


Greenhorn  limestone,  correlation  of  66 
Greybull  sandstone,  correlation  of  58 
Gypsum,  in  Chugwater  formation..  65 


INDEX 


93 


H. 

Hancock,  E.  T.,  cited 20, 

38,  39,  40,  41,  57,  61,  84 

Hardin,  oil  and  gas  near 


76,  84 

Hares,  C.  J.,  cited  36,  38,  55,  59 

Hatcher,  J.  B.  cited  29 

Hatcher,  J.  B.,  and  Stanton,  T.  W., 


Havre  anticline,  location  of  23 

coal  near  - 73- 

gas,  occurrence  of  73,  86 

production  of  77 

Hayden,  F.  V.,  cited  41 

and  Meek,  F.  B.,  cited  — 26 

Haymaker  dome,  location  of  21 

Highwood  Mountains,  igneous  rocks 

in  57,  88 

location  of  17 

Horsethief  sandstone  characteris- 
tics of  32 

correlation  of  26,  66 

fossils  of  32 

stratigraphic  relation  of  32 

Howard  Coulee  dome,  location  of..  22 


I. 

Igneous  intrusions,  effect  on  oil 

and  gas  84 

Igneous  rocks,  occurrence  of  ....23, 

' 34,  35,  53,  54,  57,  88 

Impervious  beds,  necessity  of  79 

occurrence  of  86 

Ingomar  dome,  formations  in  43,  45,  46 
location  of  23 


J. 

Jefferson  limestone,  occurrence  of..  68 


Judith  Basin,  coal  in  . 70,  71 

Judith  Mountains,  formations  in 

43,  62,  67 

location  of  - 17 

Judith  River  formation,  character- 
istics of  44,  45 

coal  in  43,  70 

correlation  of  52,  66,  70 

distribution  of  41,  43 

gas  in  73,  86 

fossils  in  46 

thickness  of  45 

topographic  expression  of  45 

view,  showing  42 

Jurassic,  formations  of.. ..35,  62,  64,  66 

K. 

Knowlten,  F.  H.,  cited 26,  29 

Kootenai  dome,  location  of 22 

oil  possibilities  of  88 

Kootenai  formation,  characteris- 
tics of  57,  59 

coal  in  58,  59,  70 

correlation  of  58,  59,  66 

fossils  in  60 

oil  in  79,  88 

origin  of  name  57 

sections  of  

thickness  of  60 

L. 

Lakota  sandstone,  correlation  of 66 

Lance  formation,  age  of  25 

characteristics  of  31 

coal  in  71 

concretions  in  31 

correlation  of  r31,  32,  66 

distribtion  of  ..! 29 


divisions  of  31 

fossils  in  33 

oil,  and  gas  possibilities  in  areas 

of  88,  89 

origin  of  33 

origin  of  name  of  29 

stratigraphic  relation  of  26 

thickness  of  33 

topographic  expression  of  32 

view,  showing  30 

Larb  Hills,  location  of  17 

Lebo  shale,  coal  in  28 

features  of  27'  28 

Lennep  sandstone,  correlation  of 

. 26,  66 

features  of  32,  38 

Lewistown,  coal  near  ’ 70 

Lignite,  occurrence  of  70 

utilization  of  ' 72 

Little  Belt  Mountains,  formations  in 

43,  58,  59,  60,  61,  62,  64,  68 

location  of  17 

structure  of  21 

Little  Belt-Big  Snowy  anticliorium, 

features  of  22 

Little  Elk  dome,  location  of  21 

Little  Missouri  River,  location  of..  16 
Little  Rocky  Mountains,  formations 


- - <±, 

45,  49,  51,  55,  56,  58,  60,  62,  68 

igneous  rocks  in  23,  34 

location  of  17 

Little  Sheep  Mountains,  location 

of  18 

Livingston  coal  field,  location  of....  70 
Livingston  formation,  characteris- 
tics of  53 

correlation  of  54,  66 

origin  of  name  of 53 

Lodge  Creek  anticline,  location  of..  23 

M. 

McCoy,  A.  W.,  cited  82 

McGinnis  Creek  dome,  location  of..  23 

formations  in  43,  46 

McLeod  dome,  location  of  21 

Madison  limestone,  characteristics 

of  68 

Map,  compilation  of  8 

Mapping,  methods  of  8 

Meek,  F.  B.  and  Hayden,  F.  V„ 

cited  26 

Mesozoic,  distribution  of  34 

formations  of  34,  67 

table,  showing  correlation  of  66 

thickness  of  35 

unconformity  at  base  of  62 

Metamorphism,  effect  on  oil  and 

gas  pools  83 

Methane  78 

Milk  River,  anticline  on  North 

Fork  of  22 

coal  along  16  71 

Minnekahta  lmestone,  correlation 

of  66 

Minnelusa  formation,  correlation  of  66 

Missouri  River,  location  of  16 

formations  along  34, 

38,  41,  43,  44,  45,-  47,’  49 

Moccasin  Mountains,  location  of 17 

structure  of  22 

Montana  group,  divisions  of  35 

origin  of  name  of  36 

thickness  of  38 

Mook,  C.  C.,  cited  61 


94 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


Morrison  formation,  characteristics 

of  

distribution  of  „ 

fossils  of  _ 

origin  of  name  of  

sections  of  

thickness  of  ;_j_ 

Mosby  dome,  location  of  22, 

oil  development  in  

Mowry  shale,  characteristics  of 

correlation  of  

source  of  oil  and  gas : 

Musselshell  River,  location  of  


formation  along  34,  38, 

43,  44,  45,  47,  50,  54,  57,  85, 

N. 

Niobrara  shale,  stratigraphic  rela- 
tion of  36,  55, 


O. 

Oil,  association  with  coal  

with  salt  water 

migration  of  

nature  of  .' 

origin  of  

plate  showing  occurrence  of  

production  of  

theories  of  accumulation  of 

Oil  pools,  relation  to  drainage 


areas  80, 

to  steep  dips 79. 


Oil  sands,  economic  depth  of 

erosion  of  

water  saturation  of  

Oiltana  dome,  location  of  

Oligoc'ene,  formations  of  

Opeche  formation,  correlation  of-.. 

Ordovician,  occurrence  of  

Organic  origin  of  oil  and  gas 

P. 

Pahasapa  limestone,  correlation  of.. 

Paleozoic,  distribution  of  

Parkman  sandstone,  correlation  of 

Parties,  organization  of  

Peale,  A.  C.,  cited  67, 

Peay  sandstone,  stratigraphic  rela- 
tion of  

Pepperberg,  L.  S.,  cited  

Petroleum.  See  oil — 

Petroliferous  rocks,  detection  of.... 

Petroliferous  shales,  origin  of 

Pierre  shale,  occurrence  of  

Piney  Butte,  location  of 

Piniele  Ridge,  location  of  

Pipe  lines,  from  Mosby  oil  field. .. 
Pirsson,  L.  V.  and  Weed,  W.  H., 

cited  i 

Pole  Creek  anticline,  location  of.... 

Poplar  dome,  location  of  

Porcupine  dome,  formations  in 

38,  44,  45,  46,  51, 

terraces  on  

Porous  rocks,  influence  on  oil,  gas 

accumulation  

stratigraphic  relation  of  

Potter  Basin  dome,  location  of 

Powder  River,  location  of  

Pryor  Mountains,  formations  in 

35,  57,  58,  60,  62,  65, 

location  of  

Q. 

Quadrant  formation,  characteristics 
of  


correlation  of  ..  66 

distribution  of  67 

oil  in  76 

origin  of  name  of  j 67 

section  of  68 

source  of  oil  85,  86 

thickness  of  68 

R. 

Ragged  Point  dome,  location  of  ....  22 

Red  Lodge,  coal  at  71,  72 

Red  Rock  Coulee  anticline,  location 

of  23 

Reeves,  Frank,  cited  30 

Rogers,  G.  S.,  cited  27,  28 

Rosebud  River,  location  of  16 

Rosebud  Mountains,  location  of....  18 

S. 

Salt  water,  association  with  oil  and 

gas  78 

Schu chert,  Charles,  cited  26,  61 

Scobey  anticline,  location  of  23 

Scoffin  Butte  anticline,  location  of  22 

Seven  Mile  dome,  location  of 24 

Shawmut  anticline,  location  of  20 

oil  possibilities  of  88 

Sheep  Mountains,  location  of  18 

Signal  Butte  anticline,  location  of...  54 

Skull  Butte  dome,  location  of 21 

Smith,  C.  D.,  cited  31 

Smoky  Buttes,  location  of  18 

Soap  Creek  anticline,  location  of-..  76 

oil  in  76 

Spearfish  formation,  correlation  of  66 
Stanton,  T.  W.,  cited  29 


and  Hatcher,  J.  B.,  cited 

38,  41,  44.  45,  46,  53 

Stebinger,  Eugene,  cited— 21,  27, 

31,  32,  36,  40,  45,  52,  56,  64,  71,  72 

Stillwater. Valley,  coal  in  70 

St.  Mary  River,  location  of  16 

St.  Mary  River  formation,  correla- 
tion of  27,  66 

Stockett  dome,  location  of  21 

Stone,  R.  W.,  cited  29 

and  Calvert,  W.  R.,  cited 

28,  32 

Structure,  major  features  of  20,  24 

of  Central  Montana... .16,  20 
of  Eastern  Montana.... 16,  20 
Structures  favorable  to  oil  and  gas 

accumulation  80 

plate  illustrating  81 

Sumatra  anticline,  location  of  ....  23 
Sundance  formation,  correlation 

of  46,  66 

section  of,  in  Bighorn 

Mountains  64 

Sweetgrass  arch,  formations  in 

35,  38,  54 

location  of 20 

structure  of  21 

Sweetgrass  Hills,  coal  near  71 

formations  in  34,  50,  62 

gas  near  73,  74 

igneous  rocks  in 23 

location  of  17 

structure  of  21 

T. 

Tensleep  sandstone,  correlation  of 

66,  67,  86 

Tenspot  oil  well,  West  Mosby  dome  86 

Threeforks  shale,  description  of—  68 


61 

60 

62 

60 

61 

61 

74 

76 

56 

66 

85 

16 

89 

66 

78 

78 

80 

78 

78 

81 

77 

78 

87 

87 

82 

88 

88 

22 

19 

66 

68 

78 

66 

67 

45 

8 

85 

55 

71 

79 

78 

36 

18 

18 

76 

22 

23 

23 

54 

23 

79 

86 

21 

16 

67 

17 

68 


INDEX 


95 


Thermopolis  shale,  stratigraphic  re- 
lations of  55,  66 

Tongue  River,  location  of  16 

Topography,  general  description 

of  16,  18 

Torchlight  sandstone,  stratigraphic 

position  of  — 55 

Trail  Creek  coal  field,  carbon 

ratios  in  .. 89 

location  of  70 

Triassic,  formation  of  35,  65,  67 

Two  Medicine  formation  .character- 
istics of  52,  53 

coal  in  3Z,  71 

correlation  of  52,  66 

fossils  in  53 

origin  of  name  52 

topographic  expression  of  53 

U. 

Unconformities,  occurrence  of— .19,  62 

V. 

Virgelle  sandstone,  characteristics 


of  50 

correlation  of  50,  66 

distribution  of  49 

origin  of  name  49 

W. 

Washburne,  C:  H.,  cited  50 

Water  in  sands,  effect  on  oil  and 

gas  accumulation  80 


Water,  salt,  association  with  oil 

and  gas  78 

Weed,  W.  H.,  cited  49,  53,  68 

and  Pirsson,  L.  V.,  cited—  22 

West  Mosby  dome,  location  of 22 

oil  development  in  76 

plate  illustrating  75 

production  of  oil  wells  in  76 

White,  C.  A.,  cited  54 

White,  David,  cited 79,  82,  83 

White  River  beds,  age  of  19 

unconformity  at  base  of 19 

Willow  Creek  anticline,  location  of  22 
Willow  Creek  formation,  correla- 
tion of  27 

Winchester,  D.  E.,  et  al,  cited 

31,  32 

Winifred,  Fergus  County,  faulted 

structure  near  23 

Wolf  Mountains,  location  of 18 

Wolf  Point  anticline,  location  of....  23 
Woman’s  Pocket  anticline,  location 

of  23 

oil  development  in  74 

oil  possibilities  of  87 

Woodruff,  E.  G-.,  cited  29 

Woolsey,  L.  H.,  et  al,  cited 27,  28 

Y. 

Yellowstone  River,  location  of 16 

Yellowstone  Yalley,  formation  in 

34.  35.  38,  40,  41, 

43r  45,  47,  51,  53,  54 


Columnar 

Sections 


] (After  Slebinger) 

Lance  Shale 
and  Sandstone. 

1000 

3 ear pa-tv  Shade 
Some  Sandstone1 

sod 

7ivo  /Medicine 
Shale,  Sandstone 
and  some  coaZ. 

2000 

± 

Eagle  Sand  - 
stone 

29±0 

Colorado  Shade 
so  me  Sandstone- 

i&od 

Kcotenaidforrison, 
Sandstone  and. 
Shale 

900 ' 

± 

Lilts  Sha7e, 
Limestone  and. 
Sandstone 

Z7S 

± 

2<(Afte  r Collier) 

3 eaa~ paw 

Shade 

9od 

± 

Jud  itdvjtiver 
Sandstone 

400 

C lagged: 
Shade 

iso' 

Eagle 
Sew  teds  tone 

loo' 

± 

Co  lo  7xzdo  Shale 
some  Sandetorvs 

/sod 

± 

Kootsrial-Jifor- 
rison-  Sand- 
stone Shade 

62S 

± 

Lilts  Sandstone 
and  Shade 


400 

± 


^4.fbsr  3oyven) 


Lance  Shade 


IOOO 


and  Sandstone  ± 


3eccrpccw 

Shuzde 


JudiddvLt 

SancLsts 

some 


Cla. 


IOOO 

aver 
yne  and 
■ Shade 

sod 

± 

ggett 

Shade 

400' 

± 

Eagle 

Sandstone 

zgd 

Colorado  Shade 
some  Sandstone 

Z2od 

KootenaL  Shale 
and  Sandstone 

25d 

A 

EortZJnzors  ■ 
SandstD7ie,SJiaZe 

and  Ligrlde 

Lance  Shade 
and  Sandstone 

(500 

3&<arpaov 
. Shade 

900 

J'uddddv  Jtere  r 
Sandstone 

loo' 

Claageth 

Shade 

4od 

Eagle 

Sandstone 

loo' 

Colorado  Shale 
some  Sand- 
stone and 
3 imestorie 

2/00 

± 

3<W 


V^TJ 


C Z Ol  c o 

S3 11 W Ml  31VDS 

iz6i 

Mii\[Jo  nvaana 

WJJS  VNVXMOR 

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^uiAvoqs 


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UNIVERSITY  OF  MONTANA  BULLETIN 

BUREAU  OF  MINES  AND  M ETALLU RGY  SERI ES  NO.  5 


THE  LOCATION,  REPRESENTATION  AND 
PATENTING  OF  MINERAL  LANDS 
IN  MONTANA 

PROSPECTING  AND  LEASING  OF  COAL,  OIL, 
OIL  SHALE,  GAS,  PHOSPHATE  AND 
SODIUM  DEPOSITS 


By  A.  E.  AD  AMI. 

| tiC  Uttwtm  U ' 


m 2 G 1825 

UNIVERSITY  OF  SLUNOIS 

STATE  SCHOOL  OF  MINES 
BUTTE,  MONTANA. 


AUGUST  1923 


STATE  BUREAU  OF  MINES  AND  METALLURGY. 

CRAVEN,  GEORGE  W Director 

B.  S.  Massachusetts  Institute  of  Technology,  1898. 

AD  AMI,  ARTHUR  E... Mining  Engineer 

E.  M.  Montana  State  School  of  Mines,  1907. 

LAMBERT,  GERALD  S ...Assistant  Geologist 

B.  S.  School  of  Mines  and  Engineering,  Univ.  of  Utah, 
1919. 


PUBLICATIONS. 

No.  1.  The  Montana  State  Bureau  of  Mines  and 
Metallurgy  (an  explanation  of  its  purpose  and  operation). 

No.  2.  Directory  of  Montana  Metal  and  Coal  Mines. 

No.  3.  Mechanical  Ore  Sampling  in  Montana  (by 
H.  B.  Pulsifier). 

No.  4.  Geology  and  Oil  and  Gas  Prospects  of  Central 
and  Eastern  Montana  (with  a geologic  map).  (By  C.  H. 
Clapp,  Arthur  Bevan,  and  Gerald  S.  Lambert). 

No.  5.  The  Location,  Representation,  and  Patenting 
of  Mineral  Lands  in  Montana. 

Prospecting  and  Leasing  of  Coal,  Oil,  Oil  Shale,  Gas, 
Phosphate,  and  Sodium  Deposits.  (By  A.  E.  Adami). 


^ S'  -4.  t/,  36  'z  7 


PREFACE. 


^22 . 6 ? 
/vinte?  u- 

'yu>  • 6" 


This  bulletin  deals  mainly  with  interpretations  of  the  federal  and 
state  mining  laws  as  related  to  the  discovery,  location,  representation, 
and  patenting  of  mineral  land  in  the  state  of  Montana.  Considerable 
space  has  been  given  to  rules  and  regulations  pertaining  to  the  Leasing 
Act,  as  approved  by  Congress  on  February  25,  1920,  which  relates  to 
the  mining  and  prospecting  of  mineral  deposits  of  coal,  phosphate,  oil, 
oil  shale,  gas  and  sodium.  The  last  part  of  the  bulletin  includes  many 
sections  of  the  mining  laws  of  Montana  as  taken  from  the  Revised  Codes 
of  1921.  These  sections  treat  with  the  laws  of  location  and  representa- 
tion, and  laws  which  apply  to  the  actual  mining  of  mineral  deposits,  and 
mine  operations. 

This  work  has  been  written  with  the  intentions  of  supplying  the 
prospector  and  locator  of  mineral  deposits  with  such  information  as  will 
aid  him  in  complying  with  the  laws  from  the  time  of  discovery  to  such 
time  as  a patent  is  obtained,  and  to  inform  any  qualified  applicant  as 
to  the  general  procedure,  necessary  to  prospect  and  lease  lands  containing 
mineral  deposits  as  covered  by  the  Leasing  Act. 

The  information  contained  in  this  bulletin  has  been  obtained  from  the 
Regulations  of  the  United  States  Land  Office,  and  from  the  various 
treatises  on  mining  laws,  namely,  Lindley  on  Mines,  Morrison’s  Mining 
Rights,  Howell  on  Lode  and  Placer  Claims,  Ricketts  on  Mines,  and  Shamel 
on  Mining,  Mineral  and  Geological  Law. 

The  writer  wishes  to  acknowledge  his  indebtedness  to  these  treatises, 
and  to  Dr.  C.  H.  Clapp  and  Prof.  W.  T.  Scott  for  their  kind  assistance 
in  the  preparation  of  this  work. 

The  writer  is  especially  indebted  to  Mr.  Samuel  Barker,  Jr.,  E.  M., 
and  to  Mr.  E.  B.  Howell,  LL.  B.,  who  have  given  their  valuable  time 
to  reading  the  bulletin  besides  offering  many  valuable  suggestions,  and 
contributing  knowledge  gained  from  practice  in  their  professions. 

A.  E.  ADAMI. 


3 — 


CONTENTS 


Mineral  Land : Definition  


Page 


Land  Subject  to  Location  in  Montana 

State  Lands  : Location  on 

Lands  not  Subject  to  Location  in  Montana 

School  Lands  

Agricultural  Land  .. 

Before  Patent  is  Issued 

Locations:  Who  may  Locate 

Citizens  

Aliens  - 

Corporations  

Number  of  Locations . Allowed 

Kind  of  Claims 

Lode  Claims.. 

Placer  Claims 

Tunnel  Claims 

Millsites  

Coal  Land  on  State  Land 

Coal  Claims  on  Government  Land  in  a State 

Oil  and  Gas  Land : On  State  Land 

On  Government  Land 

Stone  Claims  : On  Government  Land 

On  State  Land 


Location  of  Lode  Claims  

Valid  Location  

Discovery  

Location  Notice : What  It  Should  Contain 

Notice  of  Location : Form  for 

Posting  of  Notice  of  Location 

Marking  Location  on  the  Ground : How  and  When 

Corners  : Kind  

Size  of  Claims  Located : Section  2320,  Revised  Statutes 


Discovery  Work  on  Lode  Claims 

Overlapping  Locations  

Discovery  Shaft  

Discovery  Cut  or  Tunnel 

Certificate  of  Location 17, 

Verification  of  Location  Certificate 

Annual  Labor,  Representation  Work,  Assessment  Work 

Annual  Labor  on  Group  of  Claims *. 

When  Annual  Work  Ends I 

What  Will  Count  as  Annual  Labor 

Affidavit  of  Annual  Labor : Time  for  Same 

Co-owners  

Forfeiture  of  Co-owners’  Interest : “Advertising  Out” 

Forfeiture  - 

Abandonment  

Amended  Location  

Patenting  a Mineral  Claim 

Only  Citizens  May  Secure  Patent 

How  to  Obtain  Patent 23 

When  Made  by  Authorized  Agent 25 


— 4 — 


CONTENTS 


5 


Page 


Form  for  Application  to  IT.  S.  Surveyor  General  for  Survey  of  Mining 

Claim  - - 

Adverse  Claim : Section  2326  Revised  Statutes 

Revised  Statutes  Pertaining  to  Rights  of  Possession  and  Extralateral 

Rights  

Placer  Locations  : How  Made 

Location  of  Placer  Claims  : Size — On  Public  Lands 

Form  for  Placer  Locations 

Form  for  Certificate  of  Placer  Location 


26 

29 

29 

30 

31 

32 


Discovery  Work  and  Annual  Labor 34 

Patenting  Placer  Claim 34 

Vein  or  Lode  Within  Placer  Claim 34 

Forfeiture,  Abandonment,  Relocation,  Co-owners  of  Placer  Claims 35 

Tunnel  Claims.  Location 35 

Patent  for  Tunnel  Claim 36 

Labor  on  Tunnel  Claim  36 

Staking  Lode  Claims  on  Surface 36 

Millsites,  Location  of 37 

Form  for  Millsite  Location 37 

Patenting  Millsites 37 

Millsite  for  Owner  of  Patented  Claims 38 

Timber  and  Timber  Lands 38 


Leasing  Act  of  Feb.  25,  1920  38 

Lands  Affected  - 38 

Title  to  Such  Lands.  Permit  and  Lease 39 

Who  May  Receive  a Permit  or  Lease 39 

Aliens  39 

Number  of  Leases  Allowed . 39 

Unlawful  Fights  of  Persons  or  Corporations 39 

Interests  Acquired  by  Descent,  Will,  Judgment,  etc 40 

Lawful  Combined  Interests,  for  Pipe  Lines — Railroad 40 

Unlawful  Combined  Interests 40 

Application  for  Permits  or  Leases 40 

Cancellation  of  Prospecting  Permits 40 

Permits  and  Leases  on  Land  Patented  with  Mineral  Rights  Re- 
served   40 

Right  of  Way  lor  Lipe  Lines - 41 

Right  of  Way  Over  Lands  Held  Under  Permit  or  Lease 41 

Reserving  of  Surface  Rights : of  Lands  Leased 41 

Assigning,  Sub-Leasing  41 

Relinquishment  of  Lease 41 

Methods  for  Working  Deposits  41 


Coal  Lands  42 

Permit  and  Lease 42 

Discovery  of  Coal  by  the  Permittee — Lease 42 

Railroads  42 

Areas  that  May  Be  Leased 42 

Method  of  Leasing 42 

Application  of  Leases  to  Land  Occupied  and  Improved 43 

Leasing  Additional  Land 43 

Consolidation  of  Leases 43 

Non-Contiguous  Land  43 

Royalties  and  Rentals — 43 

Period  of  Lease 43 

License  to  Cities  and  Individuals  for  Domestic  Purposes 43 

Phosphate  Lands 44 

Size  of  Lease — Shape 44 

Lease  on  Unsurveyed  Land 44 


6 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


Page 

Royalties  and  Rentals ; 44 

Period  of  Lease . . - 44 

Suspension  of  Operation 45 

Additional  Lands  45 

Oil  and  Gas  Lands...  45 

Permit  for  Unappropriated  Lands 45 

No  Permits  for  Land  in  Known  Oil  or  Gas  Field 45 

Location  of  Lands 45 

Preference  Right  to  a Permit. 45 

Terms  and  Conditions  of  Permit... 45 

Work  Required 46 

Location  of  Wells  for  Prospecting  or  Lease 40 

Precautions  When  Drilling 46 

Extension  of  Life  of  Permit... _.  46 

Discovery  of  Oil  or  Gas 46 

Royalty  Before  Applying  for  Lease 46 

Description  of  Land  Selected  for  Lease 46 

Life  of  Lease 47 

Royalties  and  Rental  Upon  Leased  Land — 47 

Reduction  of  Royalty 47 

Leasing  of  Land  in  a Producing  Oil  or  Gas  Field 47 

Preference  Right  of  Owner  of  Surface 47 

Application  by  Other  Persons 48 

Government  to  Extract  Helium  From  Gas 48 

Oil  Shale  Lands 48 

Size  of  Lease 48 

Period  of  Lease 48 

Royalties  and  Rental 48 

Claims  Held  Under  Former  Laws 48 

Sodium  Lands  4b 

Permit  49 

Lease  - - 49 

Royalty  49 

Known  Deposits  of  Sodium 49 

Rental  49 

Period  of  Lease 49 

Additional  Lands  49 

Mining  Laws  of  Montana,  Revised  Codes  of  1921 50-55 

Location  of  Mining  Claims  on  State  Lands,  Revised  Codes 55 

Sale,  Leases  and  Rentals  of  State  Lands,  Revised  Codes 56-57 

Mining  Partnerships,  Revised  Codes 58-59 

Fraud  in  Selling  Mines,  etc.,  Revised  Codes 59 

Safety  to  Underground  Miners,  Revised  Codes 59-60 

Code  of  Signals  in  Metal  Mines,  Revised  Codes 61-62 

Procedure  to  Examine  Adjoining  Mining  Properties,  Revised  Code 63 

Destroying  Notices,  Penalty,  Revised  Codes 64 


THE  LOCATION,  REPRESENTATION,  AND  PAT- 
ENTING OF  MINERAL  LANDS  IN  MONTANA. 


Mineral  Land : Definition. 

Land  which  has  been  classified  as  more  valuable  for  its  mineral 
deposits  than  for  other  purposes  is  called  mineral  land.  In  many  cases 
land  which  is  yet  unclassified  by  the  land  department  of  the  government 
may  he  more  valuable  for  its  mineral  content  than  for  other  purposes 
and  might  therefore  be  called  mineral  land.  In  case  of  dispute,  the 
final  decision  as  to  the  true  character  of  the  land  is  made  by  the  federal 
land  department,  or  by  the  different  courts. 

Unappropriated  land,  upon  or  within  which  mineral  is  found,  is  not 
classed  as  mineral  land  unless  the  deposits  are  of  sufficient  size  and 
value  to  warrant  the  expenditure  of  time  and  money  for  the  purpose  of 
prospecting  and  developing  the  deposits,  and  unless  the  land  proves 
more  profitable  for  mining  than  for  other  purposes. 

Land  Subject  to  Location  in  Montana: 

All  mineral  land  on  the  public  domain  of  the  United  States  within 
the  State  of  Montana,  whether  surveyed  or  unsurveyed,  is  open  to  loca- 
tion. Following  is  Section  2319  of  the  Revised  Statutes  of  the  United 
States,  as  enacted  on  May  10,  1872,  and  which  is  still  in  force: 

“All  valuable  mineral  deposits  in  lands  belonging  to  the  United  States, 
both  surveyed  and  unsurveyed,  are  hereby  declared  to  be  free  and  open 
to  exploration  and  purchase,  and  the  lands  in  which  they  are  found  to 
occupation  and  purchase,  by  citizens  of  the  United  States  and  those 
who  have  declared  their  intention  to  become  such,  under  regulations 
prescribed  by  law,  and  according  to  the  local  customs  or  rules  of  miners 
in  the  several  mining  districts,  so  far  as  the  same  are  applicable  and  not 
inconsistent  with  the  laws  of  the  United  States.” 

A valid  location  can  also  be  made  on  a forest  reservation. 

State  Lands:  Location  on 

In  Montana  lode  or  quartz  claim  location  may  be  made  on  mineral 
land  owned  by  the  state.  A locator  of  state  land  must  comply  with  the 
regular  laws  of  the  state  pertaining  to  the  location  of  claims,  except 
that  no  notice  of  location  need  be  recorded  in  the  office  of  the  County 
Clerk  and  Recorder,  hut  should  be  filed  with  the  Register  of  State 
lands.  After  one  year  the  locator  must  purchase  the  claim  at  not  less 
than  $10.00  per  acre,  or  lease  the  same  from  the  State  Board  of  Land 
Commissioners.  The  land  must  be  mineral  land  and  be  more  valuable 
for  mining  than  for  other  purposes.  A lode  or  quartz  claim  may  not 
be  located  on  any  coal  or  oil  lands  belonging  to  the  state.  (See  page  55.) 

Lands  not  Subject  to  Location  in  Montana: 

Any  land  which  has  been  reserved  by  the  government  for  military 
purposes,  school  purposes,  for  Indian  reservations,  or  for  public  parks 
cannot  be  located  for  mineral.  If  a reservation  has  been  abandoned  by 
the  government  and  restored  to  the  public  domain  it  is  again  subject 
to  location. 


— 7 — 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


Locations  on  Forest  Reservations  are  not  included  in  the  above  ex- 
ceptions. A special  act  was  passed  by  Congress  dated  March  3.  1891, 
withdrawing  certain  lands  from  the  public  domain  for  forest  reservations, 
but  in  1898  Congress  passed  another  law  whereby  all  mineral  land  in 
such  forest  reservations  is  subject  to  location  and  entry  as  mining 
claims. 

Following  is  a list  of  Indian  Reservations  opened  to  the  public,  and 
therefore  subject  to  location  according  to  the  mineral  laws  of  the  state : 

Fort  Belknap,  Montana,  June  10,  1896.  (Minimum  price  per  acre 
$10.00)  Blackfeet  Reservation,  Montana,  June  10,  1896.  Flathead 

Reservation,  Montana.  April  23,  1904.  Crow  Indian  Reservation,  Mon- 
tana, April  27,  1904.  (Price  of  mineral  land  as  provided  by  law,  but  in 
no  case  less  than  $4.00  per  acre.) 

Land  which  has  been  granted  to  a railroad,  and  for  which  title  passed 
to  the  railroad  company,  is  no  longer  free  and  open  to  location. 

School  Lands: 

Congress  has  reserved  Sections  16  and  36  in  each  township  in  the 
State  of  Montana,  and  has  granted  the  same  to  the  state  for  the  main- 
tenance of  public  schools,  providing,  however,  that  these  sections  have 
been  classified  by  proper  authority  as  non-mineral  in  character.  The 
classification  of  the  school  sections  is  usually  made  immediately  after 
they  have  been  surveyed  and  approved.  If  the  land  is  found  to  be 

mineral  in  character,  it  is  not  included  in  the  grant,  and  is,  therefore, 

open  to  location.  If  the  land  has  been  otherwise  appropriated,  or  if  a 
mineral  location  has  been  made  before  the  land  has  been  surveyed,  it  is 
likewise  not  included  in  the  grant. 

Agricultural  Land: 

Where  a patent  has  been  issued  for  a homestead,  and  title  thus 
granted,  it  is  impossible  for  a valid  mineral  location  to  be  made,  unless 
fraud  has  been  committed  in  obtaining  the  agricultural  patent.  In  case 
of  fraud,  a suit  by  the  United  States  to  vacate  and  annul  patents,  must 

be  brought  within  six  years  after  the  date  of  issuance  of  patent,  other- 

wise the  patent  is  good.  (Act  March  3,  1891).  If  a valuable  mineral 
deposit  has  been  discovered  on  agricultural  land  for  which  patent  has 
been  issued,  the  deposit  may  hot  be  located  by  a third  party.  Such  a 
deposit  can  be  worked  or  prospected  only  subject  to  the  wishes  of  the 
owner  under  patent. 

Before  Patent  is  Issued: 

If  a homestead  is  applied  for  in  the  local  land  office,  and  patent  has 
not  been  issued,  it  will  be  possible  for  a valid  mineral  location  to  be 
made  providing,  however,  that  sufficient  mineral  can  be  found.  In  case 
of  dispute  between  the  agricultural  and  mineral  locators,  it  is  necessary 
to  have  the  Land  Office  determine  the  character  of  the  land,  and  if 


LOCATION,  REPRESENTATION,  PATENTING  MINERAL  LANDS  9 

any.  portion  of  the  land  in  conflict  is  proved  to  be  mineral  land  by  the 
legal  authorities,  it  will  be  open  to  location,  and  the  homestead  entry 
for  that  portion  in  conflict  will  be  cancelled. 

Locations:  Who  may  locate — 

Citizens : 

Any  citizen  of  the  United  States  or  anyone  who  has  declared  his  in- 
tention to  become  a citizen  may  locate  mineral  land  for  the  purpose  of 
prospecting  and  developing  the  same. 

Aliens : 

An  alien  may  locate  a claim  in  the  State  of  Montana,  and  can  hold, 
prospect,  or  develop  it,  and  his  rights  will  be  protected  by  the  laws  in 
so  doing,  providing  that  he  otherwise  complies  with  the  state  laws 
governing  the  location  of  mining  claims,  and  all  ore  that  is  discovered 
and  mined  may  be  sold  or  otherwise  disposed  of  as  desired  by  the  alien 
locator.  The  Montana  law  states  that : 

“Any  person  who  discovers,  upon  the  public  domain  of  the  United 
States,  within  the  State  of  Montana,  a vein,  lode,  or  ledge  of  rock  in 

place,  bearing  goltn  silver,  etc.,  as  a placer  deposit  of  gold  or  other 

deposit  of  minerals  having  a commercial  value,  which  is  subject  to  entry 
and  patent  under  the  mining  laws  of  the  United  States,  may,  if  qualified 
by  the  laws  of  the  United  States,  locate  a mining  claim  upon  such  vein, 
lode,  or  ledge  or  deposit,  etc.” 

In  several  cases,  as  decided  by  the  courts,  it  has  been  held  that  a 

location  by  an  alien  is  not  void  but  voidable,  1The  right  of  an  alien  to 

hold  a mineral  location  may  be  contested  by  the  Government  only,  and 
an  alien  may,  therefore,  hold  a claim  indefinitely  by  right  of  location 
Should  the  alien  later  declare  his  intention  to  become  a citizen,  his 
location  would  become  valid,  and  his  rights  would  date  back  to  the 
time  of  location.  An  alien  may  purchase  a patented  claim  in  Montana, 
or  acquire  title  to  the  same  otherwise,  in  which  case  he  has  the  same 
rights  as  any  citizen. 

Corporations : 

Any  association  or  partnership  composed  of  citizens  and  corporations, 
organized  under  the  laws  of  any  state,  or  of  the  United  States,  may 
locate  mining  claims.  A corporation  is  not  legally  considered  an  asso- 
ciation, and  therefore  it  may  not  locate  a placer  claim  of  more  than 
twenty  acres. 

A valid  location  may  be  made  by  an  agent  for  another  person  or  per- 
sons, including  corporations  and  partnerships.  A minor,  regardless  of 
sex.  may  also  locate  a claim  and  hold  the  same. 

United  States  Mineral  Surveyors,  officers,  clerks,  and  employees  of 
the  General  Land  Office,  may  not  locate  nor  patent  a mining  claim. 

Number  of  Locations  Allowed: 

The  number  of  locations  that  one  person  may  make  is  unlimited  by 
the  state  law,  but  as  a prospector  or  locator  is  usually  limited  with 
capital  and  time,  the  number  of  claims  that  he  may  legally  hold  is  more 


lHowell  on  Lode  and  Placer  Claims,  page  7. 


10  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

or  less  limited  thereby.  It  is  necessary  that  $100.00  be  spent  on  each 
claim  each  year,  or  in  case  of  a group  of  claims,  the  annual  work  for  all 
of  the  claims  may  be  performed  under  certain  conditions,  on  any  one  of 
the  claims  if  not  less  than  $100.00  is  spent  for  each  claim  so  repre- 
sented. This  annual  work  is  also  known  as  “Representation  Work”. 
(See  Location  Page  20.) 

Kinds  of  Claims: 

Lands  may  be  located,  under  certain  conditions,  for  mining  purposes 
as  lode,  placer,  tunnel,  millsite,  coal,  oil,  oil  shale,  gas,  phosphate  or 
sodium  claims. 

Lode  Claims: 

Lode  claims  are  understood  to  be  mining  claims  on  which  valuable 
mineral  has  been  found  in  place,  and  any  mineral  land  on  the  public 
domain  of  the  United  States  which  has  not  been  otherwise  appropriated 
may  be  located  as  a lode  claim.  By  the  phrase  “mineral  in  place”  is 
meant  mineral  which  is  fixed  or  enclosed  in  the  country  rock. 

The  terms  “vein”,  “lode”,  “lead”,  “ledge”,  are  used  synonymously  by 
the  prospector  and  locator,  and  hence  may  be  considered  synonymous 
when  making  locations,  although  from  a geological  standpoint,  these 
terms  are  not  identical  in  meaning. 

A vein  is  a tabular  or  sheet-like  mineral  deposit  found  in  connection 
with  some  pre-existing  fissure  or  cavity.  A lode  or  lead  has  been 
formed  in  connection  with  a series  of  nearly  parallel,  closely  spaced 
fractures,  and  may  therefore,  consist  of  several  veins.  A ledge  refers 
to  a vein  having  a large  and  prominent  outcrop. 

Placer  Claims : 

A placer  claim  may  be  a claim  located  on  mineral  land  containing 
mineral  deposits  in  a loose  state,  that  is  not  in  place.  Mineral  deposits 
found  in  a loose  state  may  be  rightly  called  placer  deposits.  According 
to  the  laws  of  the  United  States,  the  following  minerals  may  be  located 
as  placer  deposits : alum,  asphaltum,  diamonds,  guano,  gypsum,  kaolin 

or  china  clay,  marble,  mica,  onyx,  slate,  building  stone  and  limestone  for 
fluxe§  or  smelting  purposes.  Clay  used  for  manufacturing  brick  is  not 
considered  a mineral,  and  such  clay  deposits  must  be  located  as  agri- 
cultural land.  Abandoned  tailings  may  be  located  as  a placer  deposit. 

Tunnel  Claims: 

A tunnel  claim  is  one  located  for  the  purpose  of  prospecting  mineral  land 
by  means  of  a tunnel.  All  veins  cut  by  the  tunnel  are  subject  to  loca- 
tion and  development  by  the  prospector  providing  no  prior  rights  to  the 
vein  existed  before  beginning  the  tunnel.  A tunnel  may  not  be  driven 
through  any  ground  which  was  located  by  another  party  prior  to  the 
date  the  tunnel  was  started,  nor  may  it  be  driven  through  any  ground 
for  which  another  person  has  a patent.  Following  is  section  2323  of  the 
Revised  Statutes  of  the  United  States,  as  passed  on  May  10,  1872,  re- 
garding tunnel  claims : 

“When  a tunnel  is  run  for  the  development  of  a vein  or  lode,  or  for 
the  discovery  of  mines,  the  owners  of  such  tunnel  shall  have  the  right 


LOCATION,  REPRESENTATION,  PATENTING  MINERAL  LANDS  11 


of  possession  of  all  veins  or  lodes  within  3,000  feet  from  the  face  of 
said  tunnel  on  the  line  thereof,  not  previously  known  to  exist,  discovered 
in  such  tunnel,  to  the  same  extent  as  if  discovered  from  the  surface ; and 
locations  on  the  line  of  said  tunnel  of  veins  or  lodes  not  appearing  on  the 
surface,  made  by  other  parties  after  the  commencement  of  the  tunnel, 
and  while  the  same  is  being  prosecuted  with  reasonable  diligence,  shall 
be  invalid,  but  failure  to  prosecute  the  work  on  the  tunnel  for  six  months 
shall  be  considered  as  an  abandonment  of  the  right  to  all  undiscovered 
veins  on  the  line  of  such  tunnel.” 

By  “face”  is  meant  the  working  face  of  the  tunnel  when  it  is  entirely 
under  ground  or  actually  under  cover. 

Millsites : 

A millsite  is  a tract  of  land  not  exceeding  five  acres,  located  on  non- 
mineral land  but  not  contiguous  to  one’s  lode  location.  If  the  millsite  is 
located  with  a lode  claim  it  may  be  used  in  connection  with  the  lode 
claim  for  mining  and  milling  purposes.  A millsite  may  also  be  located 
by  an  owner  of  a quartz  mill  or  other  reduction  plant,  who  does  not 
own  a mine  or  lode  claim  in  connection  with  the  reduction  plant. 

Section  2337,  Revised  Statutes  of  the  United  States,  as  passed  May 
10,  1872,  states : 

“Where  non-mineral  land,  not  contiguous  to  the  vein  or  lode,  is  used 
or  occupied  by  the  proprietor  of  such  vein  or  lode  for  mining  and  milling 
purposes,  such  non-contiguous  surface  ground  may  be  embraced  and  in- 
cluded in  an  application  for  patent  for  such  vein  or  lode,  and  the  same 
may  be  patented  therewith,  subject  to  the  same  preliminary  require- 
ments as  to  survey  and  notice  as  are  applicable  to  veins  or  lodes ; but  no 
location  hereafter  made  of  such  non-ad jacent  land  shall  exceed  five  acres, 
and  payment  for  the  same  must  be  madn  at  the  same  rate  as  fixed  by 
this  chapter  for  the  superficies  of  the  lode.  The  owner  of  a quartz  mill 
or  reduction  works,  not  owning  a mine  in  connection  therewith,  may 
also  receive  a patent  for  his  millsite,  as  provided  in  this  section.” 

It  is  absolutely  necessary  th^t  the  land  claimed  as  a millsite  be  non- 
mineral in  character,  and  therefore,  it  should  not  contain  any  veins, 
lodes,  or  ledges  valuable  for  mineral.  By  “contiguous”  is  meant  ad- 
joining, adjacent,  touching.  A claim  and  millsite  with  only  one  corner 
in  common  has  been  held  as  not  contiguous. 

Coal  Land  on  State  Land: 

All  known  or  classified  coal  land  now  owned  or  acquired  later  by  the 
State  of  Montana  is  reserved  from  location  and  can  only  be  leased  from 
the  State  by  paying  a royalty  of  not  less  than  ten  cents  per  ton  to  the 
State.  State  coal  lands  are  so  classified  by  the  United  States  Geological 
Survey  and  by  the  State  Board  of  Land  Commissioners.1 

Coal  Claims  on  Government  Land  in  a State:  (See  page  42.) 

Oil  and  Gas  Land:  On  State  Land— 

All  state  lands  are  subject  to  sale,  or  lease  but  all  coal,  oil  and  gas 
contained  therein  is  reserved  by  the  state.  (See  page  56.) 

On  Government  Land: 

By  an  act  passed  in  Congress  in  1903  oil  lands  were  located  as  placer 
claims  and  the  annual  assessment  work  on  a group  of  claims  not  exceed - 


lLaws  of  1909,  Chapter  147.  See  pages  56  and  57. 


12  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

ing  five  in  all,  lying  contiguous  and  owned  by  the  same  person  or  cor- 
poration, was  done  on  any  one  claim,  provided  that  the  work  performed 
developed  the  adjoining  claims. 

By  an  act  as  approved  by  Congress  on  February  25,  1920,  all  lands 
containing  coal,  oil,  and  gas,  owned  by  the  United  States,  are  subject 
to  lease  only  by  citizens  of  the  United  States  and  under  certain  con- 
ditions by  citizens  of  a country  which  grants  similar  privileges  to 
American  citizens.1 

Stone  Claims : On  Government  Land : 

Lands  which  are  chiefly  valuable  for  building  stone  are  subject  to 
location  under  the  provisions  of  the  law  relating  to  placer  claims. 

Gn  State  Land: 

Land  which  is  chiefly  valuable  for  building  stone  found  on  state  land 
may  be  leased  from  the  State  Land  Commissioners  upon  a royalty  basis 
only.  (See  page  56.) 

LOCATION  OF  LODE  CLAIMS. 

Following  are  the  various  steps  from  the  time  of  discovery  to  that  of 
applying  for  patent : 

1.  Discovery  of  mineral. 

2.  Posting  Notice  of  Location. 

3.  Establishing  corners  within  thirty  days. 

4.  Performing  discovery  work  within  sixty  days. 

5.  Filing  certificate  of  location  within  sixty  days. 

6.  Performing  annual  assessment  work. 

7.  Applying  for  patent  after  $500  has  been  expended  for  development 

work. 

Valid  Location: 

Before  making  a mineral  location,  the  locator  should  first  ascertain 
whether  or  not  the  land  is  mineral  land  on  the  public  domain  of  the 
United  States,  or  on  State  land ; second,  should  discover  whether  or  not 
the  land  is  open  to  location,  and  third,  should  make  a discovery  of  mineral 
before  posting  the  location  notice. 

Discovery : 

By  discovery  of  a lode  location  is  meant  the  finding  and  locating  of 
a vein,  lode,  or  ledge  of  rock  in  place,  bearing  gold,  silver,  cinnabar,  lead, 
tin,  copper,  or  other  valuable  minerals.  When  the  land  is  unclassified, 
the  discovery  of  a vein,  lode,  or  ledge  has  to  be  of  such  character  that 
the  land,  in  the  opinion  of  the  locator,  will  prove  more  valuable  for 
mining  than  for  any  other  purposes.  A discovery  of  mineral  such  as 
gold  or  other  valuable  mineral  deposits,  is  also  necessary  in  making  a 
placer  location. 

“To  constitute  a valid  discovery  upon  a lode  mining  claim,  three 
elements  are  necessary:  (1)  There  must  be  a vein  or  lode  of  quartz  or 

other  rock  in  place;  (2)  The  quartz  or  other  rock  in  place  must  carry 
gold  or  some  other  valuable  mineral  deposit;  and  (3)  the  two  preced- 


lSee  Page  38  for  Leasing  Act. 


LOCATION,  REPRESENTATION,  PATENTING  MINERAL  LANDS  13 


ing  elements  when  taken  together  must  be  such  as  to  warrant  a prudent 
man  in  the  expenditure  of  time  and  money  to  develop  a valuable  mine”. 
(41-L.  D.  320). 

Location-  Notice:  What  it  should  contain — 

After  making  the  discovery  it  is  necessary  for  a locator  to  post  a 
Notice  of  Location  which  can  be  in  a written  or  printed  form,  containing 
(a)  name  of  the  claim,  (b)  name  of  locator  or  locators,  (c)  the  date 
of  location,  which  shall  be  the  date  of  posting  the  notice,  (d)  and  the 
approximate  dimensions  of  the  area  of  the  claim  intended  to  be  ap- 
propriated. 

Many  prospectors  or  locators  have  the  opinion  that  it  is  absolutely 
necessary  to  obtain  a printed  form  for  a Notice  of  Location.  This  need 
not  be  the  case  as  the  laws  of  the  State  of  Montana  specify  that  the 
notice  may  be  written  or  printed. 

Following  are  several  forms  of  notices  of  location  that  comply  with 
the  requirements  of  the  State  of  Montana : 

NOTICE  OF  LOCATION. 

Notice  is  hereby  given  that  the  undersigned  locator 

ha discovered  a vein,  lode,  or  ledge  of  rock  in  place,  bearing  gold, 

silver,  cinnabar,  lead,  tin,  copper,  or  other  valuable  minerals ; that  the 
same  is  hereby  located  and  claimed  under  the  provisions  of  the  laws  of 
the  United  States  and  the  State  of  Montana,  and  that  said  discovery  is 
at  or  near  where  this  Notice  of  Location  is  posted. 

The  name  of  the  claim  is  the  jl Lode  Mining 

Claim,  and  is  situated  in  the  County  of  , State  of 

Montana. 

The  approximate  dimensions  of  area  of  the  claim  hereby  appropriated 

are  as  follows : feet  in  a direction  and 

feet  in  a direction  along  the  course 

of  the  vein,  lode  or  ledge  from  the  point  of  discovery,  and  

feet  on  each  side  from  the  center  of  the  vein,  lode  or  ledge ; the  same 
being  feet  wide  by  feet  in  length. 

This  notice  of  location  is  dated  and  was  posted  on  the  claim  at  or 

near  the  point  of  discovery  this  day  of  

A.  D.  192 

Witnesses  : Locators  and  claimants  : 


A brief  form  for  Notice  of  Location  which  complies  with  all  of  the 
requirements  of  the  State  of  Montana  is  as  follows : 


14  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

NOTICE  OF  LODE  LOCATION. 

Notice  is  hereby  given  that  the  undersigned  ha discovered  a vein, 

lode,  or  ledge  of  rock  in  place  bearing  valuable  mineral  deposits,  and 

ha this  day  of  , A.  D.  192......  located 

same  as  the  Lode  Mining  Claim  by  posting  this 

location  notice  at  or  near  the  point  of  discovery. 

The  approximate  dimensions  of  the  area  of  the  claim  located  are : 

feet  in  a direction,  and  feet  in  a 

direction  along  the  vein,  lode,  or  ledge  from  the  point  of 

discovery  and  feet  on  each  side  of  the  middle  of  the  vein  or 

lode. 

Locators  and  claimants : 


Posting  of  Notice  of  Location: 

The  Notice  of  Location  must  be  posted  in  such  a manner  that  it  can 
be  readily  seen  or  found  by  persons  passing.  Common  methods  are  to 
tack  the  notice  in  a small  box  and  nail  the  box  to  a tree  ,or  to  a post 

placed  in  the  ground,  or  second,  to  place  the  notice  in  a tin  can  which  is 

nailed  to  some  tree  or  post,  or  third,  to  place  the  notice  in  a can  on 

a pile  or  rock,  etc.  This  notice  should  be  posted  in  all  cases  at  the 

point  of  discovery  or  at  least  within  a few  feet  of  the  discovery. 

Marking  Location  on  the  Ground:  How  and  when — 

Within  thirty  days  after  posting  the  Notice  of  Location,  it  is  neces- 
sary to  mark  the  location  so  that  the  boundaries  can  be  traced.  This  is 
usually  accomplished  by  establishing  some  form  of  monument,  whether 
of  stone  or  wood,  at  each  corner  of  the  claim.  Whatever  kind  of  monu- 
ment is  used  must  be  marked  with  the  name  of  the  claim  and  the  num- 
ber of  the  corner  or  cardinal  point.  (Points  of  compass,  i.  e.  the  N.  E. 
corner,  the  S.  W.  corner,  etc.) 

Corners : Kind 

The  corners  of  a claim  may  be  (1)  a tree  at  least  eight  inches  in  dia- 
meter and  blazed  on  four  sides;  (2)  a post  at  least  four  inches  square 
by  four  feet  six  inches  in  length,  set  one  foot  in  the  ground,  unless  solid 
rock  should  occur  at  less  depth,  in  which  case  the  post  should  be  set 
upon  such  rock,  and  surrounded  in  all  cases  with  a mound  of  earth  or 
rock  at  least  four  feet  in  diameter  and  two  feet  high,  (3)  a stump  four 
inches  square  and  surrounded  by  a similar  mound,  (4)  a stone  at  least 
six  inches  square  by  eighteen  inches  in  length,  set  two-thirds  of  its 
length  in  the  ground  with  a mound  of  earth  or  stone  along  side  at 
least  four  feet  in  diameter  and  two  feet  high,  or  (5)  a boulder  at  least 
three  feet  above  the  natural  surface  of  the  ground  on  the  upper  side. 

The  corners  may  be  placed  where  desired  and  also  on  any  land  previ- 


LOCATION,  REPRESENTATION,  PATENTING  MINERAL  LANDS  15 


ously  located.  Until  a claim  is  patented,  it  is  advisable  to  protect  the 
corners  by  replacing  them  if  they  are  destroyed,  thus  definitely  marking 
the  boundaries. 

Size  of  Claims  Located:  Section  2320,  Revised  statutes. 

“Mining  claims  upon  veins  or  lodes  of  quartz  or  other  rock  in  place 
bearing  gold,  silver,  cinnabar,  lead,  tin,  copper,  or  other  valuable  deposits, 
heretofore  located,  shall  be  governed  as  to  length  along  the  vein  or  lode 
by  the  customs,  regulations,  and  laws  m force  at  the  date  of  their  loca- 
tion. A mining  claim  located  after  the  tenth  day  of  May,  eighteen 
hundred  and  seventy-two,  whether  located  by  one  or  more  persons,  may 
equal,  but  shall  not  exceed,  one  tnousand  five  hundred  feet  in  length 
along  the  vein  or  lode;  but  no  location  of  a mining  claim  shall  be  made 
until  the  discovery  of  the  vein  or  lode  within  the  limits  of  the  claim 
located.  No  claim  shall  extend  more  than  three  hundred  feet  on  each 
side  of  the  middle  of  the  vein  at  the  surface,  except  where  adverse 
rights  existing  on  the  tenth  day  of  May,  eighteen  hundred  and  seventy- 
two,  render  such  limitation  necessary.  The  end  lines  of  each  claim  shall 
be  parallel  to  each  other/’ 

According  to  the  above  section  a locator  may  place  his  corners  so  that 
he  shall  have  fifteen  hundred  feet  along  the  vein  and  three  hundred  feet 
on  each  side  of  the  center  of  the  vein  at  the  surface.  This  is  the  max- 
imum size  of  a claim.  There  are  no  restrictions  as  to  the  minimum  size 
of  a claim.  An  ideal  location  is  shown  in  figure  1 or  figure  2. 


/SO  o'. 


F,£.NoJ. 


F> No  Z. 

In  figures  1 and  2,  the  end  lines  and  side  lines  are  parallel.  It  is  not 
necessary  to  have  the  sidelines  parallel,  but  no  point  on  a side  line  may 
be  more  than  300  feet  from  the  center  of  the  vein.  It  is  not  necessary 


16  MONTANA  STATE  BUREAU'  OF  MINES  AND  METALLURGY 

for  the  vein  to  be  equidistant  from  the  side  lines,  nor  is  it  necessary 
for  the  end  lines  of  a location  to  be  parallel.  Figure  3 shows  a valid 
location  claiming  fifteen  hundred  feet  along  the  vein,  with  end  lines 
parallel,  and  side  lines  three  hundred  feet  or  less  from  the  center  of 
the  vein. 


Fig.  No.  3. 


SE. 

Aoc.Cor 

Fig  No.  A. 


Figure  4 may  be  the  shape  of  a valid  location  but  before  the  same  can 
be  patented  it  will  be  necessary  to  make  both  end  lines  parallel,  and  the 
side  lines  not  more  than  300  feet  from  the  center  of  the  vein  at  any 
point. 

In  locating  a claim  the  prospector  or  locator  seldom  places  his  corners 
so  that  he  has  an  ideal  location,  or  his  end  lines  parallel,  but  his  rights 
to  prospect  and  develop  such  a claim  are  duly  protected  if  he  otherwise 
complies  with  the  laws  of  location.  A claim  is  seldom  located  by  mak- 
ing accurate  measurements  as  the  distances  are  usually  stepped  off.  Thus 
a location  is  not  invalid  because  its  length  is  slightly  greater  than  1500 
feet  or  its  width  more  than  300  feet  on  each  side  of  the  middle  of  the 
vein,  but  when  making  application  for  patent  the  dimensions  must  be 
corrected  accordingly,  to  comply  with  government  statutes. 

It  should  not  be  understood  from  the  above  statement  that  a locator 


LOCATION,  REPRESENTATION,  PATENTING  MINERAL  LANDS  17 


may  wilfully  stake  out  a claim  with  excessive  dimensions  in  order  to 
hold  additional  land  or  deprive  a third  person  from  making  a location. 
A location  that  exceeds  the  maximum  size  or  one  with  the  actual 
measurements  greater  than  stated  in  the  notice  of  location  is  void  only 
as  to  the  excess,  and  the  excess  may  be  located  by  a third  party. 

Discovery  work  on  lode  claims: 

After  posting  the  notice  of  location,  and  establishing  the  corners,  a 
certain  amount  of  work  must  be  performed  within  a definite  period, 
either  by  sinking  a shaft,  or  driving  a tunnel,  or  by  cuts  or  trench  work. 
The  object  of  this  work  is  to  prevent  the  appropriation  of  land  for  spe- 
culative purposes.  It  is  known  as  Discovery  Work  and  must  be  per- 
formed within  sixty  days  after  the  date  of  location. 

The  discovery  shaft,  tunnel,  cut,  etc.,  must  be  upon  unappropriated 
ground,  and  it  is  necessary  that  mineral  be  found  in  place  in  the  dis- 
covery. If  a vein  or  lode  is  discovered,  it  is  necessary  that  the  apex 
of  the  vein  or  lode  shall  lie  within  the  boundaries  of  the  location.  A 
location  is  not  valid  without  a discovery  of  mineral.  The  discovery 
work  may  be  performed  at  any  point  along  the  vein  within  the 
boundaries  of  the  location. 

Overlapping  Locations : 

Locations  may  overlap,  and  the  corners  may  be  placed  on  another 
claim,  but  the  discovery  work  must  be  performed  on  ground  which  does 
not  conflict  with  any  other  location,  and  it  must  be  on  unappropriated 
public  domain. 

Discovery  Shaft: 

The  discovery  work  may  be  performed  by  sinking  a shaft  to  a depth 
of  at  least  ten  feet  vertically  .below  the  lowest  point  of  the  collar  of  the 
shaft,  and  not  less  than  150  cubic  feet  of  material  must  be  excavated, 
and  the  vein  exposed.  The  Montana  law  does  not  state  any  horizontal 
dimensions  for  a discovery  shaft. 

If  the  vein  is  exposed  or  cut  at  a less  vetrical  depth  than  ten  feet, 
and  before  150  cubic  feet  of  material  is  excavated,  the  locator  may 
excavate  the  balance  of  the  material  at  another  point  on  the  claim,  but 
in  any  case  not  less  than  75  cubic  feet  of  material  must  be  excavated  at 
the  point  of  discovery. 

Discovery  Cut  or  Tunnel: 

The  discovery  work  may  be  performed  in  a cut  or  tunnel,  and  in 
Montana,  150  cubic  feet  of  material  must  be  excavated,  and  not  less 
than  75  cubic  feet  must  be . excavated  at  the  point  of  discovery.  For 
each  location,  there  must  be  a discovery,  and  the  required  discovery 
work  must  be  performed  on  each  location. 

Certificate  of  Location: 

The  State  of  Montana  requires  that  the  notice  of  location  be  filed  for 
record  with  the  county  clerk  and  recorder  of  the  county  in  which  the 
claim  is  located,  within  sixty  days  after  location.  This  record  is  known 
as  the  Certificate  of  Location,  and  in  order  to  comply  with  the  laws 


18  MONTANA  STATE  BUREAU’  OF  MINES  AND  METALLURGY 

of  the  State  it  must  contain  (1)  the  name  of  the  claim,  (2)  the  name 
of  the  locators,  (3)  the  date  of  the  location,  (4)  a description  of  the 
claim  with  reference  to  some  natural  object  or  permanent  monument  so 
as  to  identify  it,  (5)  the  direction  and  distance  claimed  along  the  lode 
or  vein  each  way  from  the  discovery  and  the  width  claimed  on  each 
side  of  the  middle  of  the  vein.  Certificates  of  Location  must  be  verified 
before  a Notary  Public,  or  other  officer  authorized  to  administer  oaths, 
by  the  locator  or  an  authorized  agent. 

Following  is  a form  of  Certificate  of  Location  which  must  be  filed 
with  the  county  clerk  of  the  county  in  which  the  claim  is  situated: 

CERTIFICATE  OF  LOCATION 
of  the 

. Lode  Mining  Claim. 

Know  All  Men  By  These  Presents,  that  the  undersigned,  on  the  

day  of  , A.  D.  19 , did  discover  a vein  or 

lode,  bearing  gold,  silver,  or  other  valuable  metals,  and  on  the  same 

day  did  locate  the  same  as  the  Lode  Mining 

Claim,  by  posting  a Notice  of  Location  at  the  point  of  discovery,  said 

notice  containing  the  name  of  the  claim,  the  name of  the  undersigned 

as  locator , date  of  location,  and  approximate  dimensions  of  the 

claim  intended  to  be  appropriated,  and  that  within  thirty  days  after 
above  mentioned  date,  the  undersigned  did  distinctly  mark  boundaries  of 
said  lode  claim  by  establishing  duly  marked  monuments  at  each  corner 
of  said  claim  as  follows : 


Corner  No.  1 the  , Corner  of  this  claim  is  a 

2 marked  3 - 

Corner  No.  1 Lode. 

Corner  No.  2 the Corner  of  this  claim  is  a 

marked  . 

Corner  No.  2 Lode. 

Corner  No.  3 the  Corner  of  this  claim  is  a 

marked  

Corner  No.  3 Lode. 

Corner  No.  4 the  Corner  of  this  claim  is  a 

marked  

Corner  No.  4 — - Lode. 


That  within  sixty  days  after  the  above  mentioned  date  of  location  the 

following  discovery  work  was  performed  4 

at  which  point  the  vein  or 

lode  was  discovered,  the  total  excavation  amounting  to  ..... 

cubic  feet. 

That  the  undersigned  locator claim  feet  in  a 

iNE  or  NW,  etc. 

2Describe  briefly  tree,  post,  boulder,  etc. 

3NE,  NW,  etc. 

4Shaft,  tunnel,  or  cut,  and  dimensions  of  each. 


LOCATION,  REPRESENTATION,  PATENTING  MINERAL  LANDS  19 


direction  and  feet  in  a . 

direction  along  the  course  of  the  vein  measured  from  the  point  of  said 
discovery  and  feet  on  each  side  of  the  center  of  the  vein. 

That  the  following  references  are  made  to  some  natural  object  or 
permanent  monument  as  will  identify  the  claim  : 

(1)  6 

(2)  

(3)  

The  following  claims  are  adjoining,  to-wit : — On  the  north . 

the  Lode  Mining  Claim.  On  the  East  the 

Lode  Mining  Claim.  On  the  South the 


Lode  Mining  Claim.  On  the  West  the 

Lode  Mining  Claim. 

This  claim  is  situated  in  the  Mining  District, 


County  of  , State  of  Montana. 

That  the  name....  of  the  locator and  the  claimant follow ; and 

the  undivided  interest  in  the  above  described  location  claimed  by  each 
of  the  undersigned  is  indicated  by  the  fraction  set  after  each  name : 

Locators  Interest 


Verification  of  Location  Certificate: 

STATE  OF  MONTANA, 

County  of 


being  first  duly  sworn,  on  oath  says : That  he  is 

the  locator and  claimant of  the  Lode 

Mining  Claim,  and  that  he  has  read  the  said  Certificate  of  Location  and 
that  the  matters  and  things  stated  therein  are  true  of  his  own  knowledge. 


Subscribed  and  sworn  to  before  me  this  day  of 

A.  I).  10 


Notary  Public  for  State  of  Montana. 

Note:  Printed  forms  for  Notice  of  Location  and  Certificate  of 

Location  can  be  purchased  at  the  different  news  stands  and  newspaper 
offices  in  the  State. 

r>State  approx,  direction  and  dist.  to  some  sec.,  corner,  patented  mining 
claim  corner,  intersection  of  gulches,  permanent  peaks,  hills,  shafts,  tunnels, 
intersection  of  streams,  towns,  RR  stations  etc. 

eName  of  locator  or  authorized  agent,  or  officer  of  corporation. 


20  MONTANA  STATE  BUREAU’  OF  MINES  AND  METALLURGY 

Annual  Labor,  Representation  Work,  Assessment  Work: 

Performing  the  necessary  work  of  location  and  discovery,  recording 
the  certificate  of  location,  and  verifying  the  same,  entitles  the  locator 
or  claimant  to  hold  the  claim  until  noon  of  the  first  day  of  July  suc- 
ceeding the  date  of  location,  but  for  each  period  of  one  year  thereafter 
at  least  $100.00  must  be  spent  for  labor  or  improvements  on  the  claim. 

Example:  If  a claim  is  located  on  March  10,  1922,  the  first  annual 

work  or  assessment  work  must  be  performed  between  noon  on  July  1, 
1922  and  noon  July  1,  1923.  If  a claim  is  located  on  July  10,  1922,  the 
first  annual  work  must  be  performed  during  the  period  from  noon  July 
1.  1923  and  noon,  July  1,  1924. 

Following  is  an  amendment  to  Act  of  January  22,  1880. 

“That  the  period  within  which  the  work  required  to  be  done  annually 
on  all  unpatented  mineral  claims  located  since  May  10,  1872,  including 
such  claims  in  Alaska,  shall  commence  at  12  o’clock  meridian  on  the  1st 
day  of  July  succeeding  the  date  of  location  of  such  claim;  Provided 
further,  That  on  all  such  valid  existing  claims,  the  annual  period  end- 
ing December  31,  1921,  shall  continue  to  12  o’clock  meridian  July  1, 
1922.”  (Approved  August  24,  1921.1 

Work  may  begin  on  the  last  day  of  the  period  within  which  the  annual 
work  must  be  performed  and  it  must  be  continued  without  interruption 
until  completed.  Continuous  work  gives  one  the  right  of  possession, 
which  until  lost,  does  not  make  a claim  subject  to  relocation  by  another 
person. 

Annual  Labor  on  Group  of  Claims: 

When  a number  of  claims  are  held  in  common,  and  are  contiguous, 
the  total  expenditure  that  would  be  necessary  to  hold  all  the  claims  in 
such  a group  may  be  made  upon  any  one  claim,  provided  such  work  bene- 
fits the  claims  of  the  entire  group.  Failure  to  perform  the  annual  work 
will  subject  the  claim  or  claims  to  relocation  unless  the  locator  resumes 
work  before  another  party  locates  the  same.  Locations  with  only  one 
corner  in  common  are  held  not  to  be  contiguous. 

When  Annual  Work  Ends: 

Annual  Labor  must  be  performed  until  the  claim  is  patented  or  at 
least  until  after  the  issuance  of  the  Register’s  Certificate.  If  the 
Register’s  Certificate  is  thereafter  cancelled  and  the  annual  labor  has 
not  been  performed,  the  claim  is  subject  to  relocation. 

What  Will  Counit  as  Annual  Labor: 

The  expenditure  of  $100.00  for  annual  labor  may  be  for  sinking 
a shaft,  driving  a tunnel  or  cross  cut,  erecting  machinery  or  a build- 
ing for  mining  purposes,  building  of  roads,  cost  of  powder,  fuse,  supplies, 
or  even  horse  hire  when  used  on  the  claim  for  operating  a whim  or 
pulling  cars.  A watchman’s  service  may  count  for  annual  labor  where 
the  improvements  on  a claim  are  valuable.  Machinery,  boilers,  and  sup- 
plies, brought  on  the  claim,  and  then  removed  or  not  used  will  not  count 
as  a part  of  the  annual  labor. 


LOCATION,  REPRESENTATION,  PATENTING  MINERAL  LANDS  21 


Affidavit  of  Annual  Labor:  Time  for  same — 

The  State  of  Montana  does  not  require  a locator  to  make  an  affidavit 
as  to  the  annual  labor  or  work  performed,  but  the  law  states  that  the 
owner  of  the  lode  or  placer  claim  who  performs,  or  causes  to  be  per- 
formed, the  annual  work  or  improvement  in  order  to  prevent  forfeiture 
of  the  same,  may  within  twenty  days  after  the  annual  labor  file  with  the 
county  clerk  an  affidavit  of  his  own,  or  of  one  of  the  persons  who  per- 
formed the  work.  This  affidavit  is  accepted  by  courts  as  prima  facia 
evidence  that  the  work  has  been  performed. 

Co-owners : 

When  there  is  more  than  one  locator  each  must  contribute  his  share 
of  the  required  amount  spent  for  annual  labor  but  when  one  of  the 
locators  or  co-owners  fails  or  refuses  to  contribute  his  share,  his  interest 
may  become  forfeited. 

Forfeiture  of  Co-owners  Interest:  “Advertising  Out” 

Upon  the  failure  of,  any  one  of  several  co-owners  to  contribute  his 
share  of  the  required  expenditures,  the  co-owners  who  have  performed 
the  labor  or  made  the  improvements  as  required,  may,  at  the  expiration 
of  the  year,  notify  the  delinquent  co-owner  in  writing  or  notice  by  pub- 
lication in  a newspaper,  published  nearest  the  claim,  for  at  least  once 
a week  for  ninety  days ; and  if,  upon  the  expiration  of  ninety  days  after 
such  notice  in  writing,  or  upon  the  expiration  of  one  hundred  eighty 
days  after  the  first  newspaper  publication  and  notice,  the  delinquent 
co-owner  shall  have  failed  to  contribute  his  proportion  to  meet  such  ex- 
penditures or  improvements,  his  interest  in  the  claim  by  law  passes  to 
his  co-owners  who  have  made  the  necessary  expenditures.  When  a 
locator  or  claimant  alleges  ownership  of  a forfeited  interest,  under  the 
above  provisions,  the  sworn  statement  of  the  publisher  as  to  the  facts 
of  publication,  giving  dates  and  a printed  copy  of  the  notice  published, 
should  be  furnished  and  the  claimant  must  swear  that  the  delinquent 
co-owner  failed  to  contribute  his  proper  share  within  the  period  fixed 
by  the  statutes.1 

Forfeiture : 

In  order  to  hold  a mining  claim  of  any  kind  in  the  State  it  is  neces- 
sary to  comply  with  the  requirements  of  the  law  in  regard  to  (1)  mak- 
ing a discovery,  (2)  posting  the  location  notice,  (3)  establishing  the 
monuments  at  the  corners,  (4)  performing  the  discovery  work,  (5)  re- 
cording the  certificate  of  location  and  verifying  the  same,  (6)  and  per- 
forming the  annual  assessment  or  representation  work.  If  any  one  of 
the  above  mentioned  requirements  are  neglected  or  not  complied  with, 
the  locator  or  claimant  may  lose  or  may  forfeit  his  rights  to  the  claim 
provided  that  another  locator  has  taken  up  the  said  claim  after  the 
expiration  of  the  time  allowed  for  any  one  of  the  above  mentioned  re- 
quirements. 

A forfeited  claim  is  subject  to  relocation,  but  a forfeiture  is  not  com- 
plete until  another  party  has  located  the  said  claim.  A locator  who  did 


lLand  Office  Regulations. 


22  MONTANA  STATE  BUREAU'  OP'  MINES  AND  METALLURGY 

not  comply  with  the  requirements  of  the  law  within  the  period  so  stated, 
but  who  at  some  later  date,  possibly  several  months  thereafter, 
did  complete  the  necessary  work  before  there  were  any  adverse  rights, 
remains  the  rightful  owner  of  the  claim,  and  his  title  to  the  same  dates 
back  to  the  time  of  location. 

Forfeiture  does  not  apply  when  an  owner  is  forceably  prevented  from 
performing  his  annual  labor. 

Abandonment : 

Abandonment  is  a voluntary  act  on  the  part  of  a locator  or  locators 
relinquishing  his,  or  their,  rights  to  the  claim,  that  is,  with  the  intention 
of  deserting  the  claim  and  thus  allowing  other  parties  to  relocate  and 
work  the  said  claim  peacefully.  An  abandoned  claim  is  subject  to  im- 
mediate relocation. 

If  the  owner  encourages  another  party  to  locate  the  claim  or  states 
before  witnesses  that  he  intends  to  leave  the  claim  with  the  intention  of 
not  returning,  it  is  an  abandonment. 

Amended  Location: 

A locator  may,  at  any  time,  amend  his  location,  and  make  any  change 
in  the  boundaries  which  does  not  involve  a change  in  the  point  of  dis- 
covery as  shown  by  the  discovery  shaft.  An  “Amended  Location  Notice” 
must  be  posted  at  the  original  point  of  discovery  the  corners  must  be 
marked  “amended”  in  addition  to  the  previous  markings,  and  an  amended 
certificate  of  location  conforming  to  the  requirements  of  an  original 
certificate,  must  be  properly  filed  and  verified. 

A defect  in  a recorded  certificate  of  location  may  be  secured  by  filing 
an  amended  certificate  of  location. 

No  additional  discovery  wcrk  need  be  performed  to  hold  an  amended 
location,  thus  differing  from  a relocation. 

Relocation : 

Any  claim  which  has  been  forfeited  or  abandoned  may  be  relocated, 
and  the  laws  pertaining  to  a location  must  be  complied  with  as  though 
it  were  an  original  location.  (See  Location  of  Lode  Claim,  Page  12). 

For  each  relocation  there  must  be  a discovery  although  the  original 
discovery  point  may  be  adopted,  and  the  original  discovery  shaft  sunk 
until  150  cubic  feet  of  material  is  excavated,  or  the  discovered  tunnel 
can  be  advanced  the  required  amount.  The  same  points  may  be  used 
for  the  corners  and  the  same  corners  may  be  used  after  being  remarked. 
A locator  or  claimant  may  relocate  his  own  claim  for  any  purpose  except 
to  avoid  the  performance  of  the  annual  labor,  or  he  may  relocate  his  own 
claim  and  change  the  boundaries  or  the  point  of  discovery,  or  both,  but 
he  must  comply  otherwise  with  all  requirements  of  the  law  in  regard 
to  an  original  location. 

If  for  some  reason  a locator  made  a valid  location  but  did  not  per- 
form the  necessary  annual  work  within  the  time  so  specified,  the  claim 
is  subject  to  relocation  by  another  party,  but  where  the  time  has  ex- 
pired for  doing  the  required  annual  work,  and  the  original  locator  again 


LOCATION,  REPRESENTATION,  PATENTING  MINERAL  LANDS  23 


intends  to  work  the  claim,  and  does  actually  resume  work,  it  is  not 
necessary  to  relocate  his  claim  to  hold  the  same,  provided  that  the 
rights  of  other  parties  have  not  intervened. 

Patenting  a Lode  Claim: 

The  annual  labor  or  assessment  work  must  be  performed  each  year, 
unless  by  a special  act  of  Congress  the  same  is  eliminated,  this  being 
the  case  for  several  years  during  the  recent  war.  In  order  to  avoid 
the  annual  work  or  in  order  to  secure  title  from  the  government,  it  is 
necessary  to  patent  one’s  claim.  Patent  may  be  applied  for  after  at 
least  $500.00  has  been  spent  on  the  claim,  or  when,  for  a group  of 
claims,  at  least  $500.00  has  been  spent  on  each  claim  in  the  group,  or 
the  equivalent  of  $500.00  for  each  claim  in  the  group  may  be  spent  upon 
any  one  of  the  claims  so  desired,  in  which  case  the  work  must  be  so 
performed  that  all  the  claims  in  the  group  will  be  developed  thereby. 

As  the  services  of  the  U.  S.  Mineral  Surveyor  will  be  required,  it  is 
advisable  for  a locator  or  claimant  to  seek  his  advice  or  the  advice  of 
an  attorney  as  soon  as  the  patent  is  desired.  All  official  surveys  of 
mining  claims,  in  application  for  patent,  are  executed  by  U.  S.  Mineral 
Surveyors  who  are  appointed  by  the  United  States  Surveyor  General  for 
the  State. 

Only  Citizens  May  Secure  Patent 

It  is  absolutely  necessary  that  a claimant  be  a citizen  of  the  United 
States,  or  one  who  has  declared  his  intention  to  become  such,  before 
patent  will  be  granted  by  the  Government. 

How  to  Obtain  Patent: 

An  application  for  an  order  of  survey  is  made  by  the  claimant  or 
his  attorney  to  the  Surveyor  General  of  the  State  in  which  the  claim 
or  claims  are  located.  The  application  may  include  the  name  of  the 
Mineral  Surveyor  whom  the  claimant  desires  to  make  the  necessary  sur- 
vey. The  Mineral  Surveyor  named  in  the  application  must  have  no  in- 
terest whatsoever  in  the  claim  or  claims  to  be  surveyed.  The  application 
must  be  accompanied  by  the  location  notice,  or  by  a certified  copy  of  the 
Certificate  of  Location,  obtained  from  the  County  Clerk  and  Recorder  of 
the  county  in  which  the  claim  is  situated,  and  by  the  sum  of  $30.00  for 
office  expenses  in  the  Surveyor  General’s  Office. 1 When  a group  of 
claims  is  to  be  surveyed  for  patent,  the  sum  of  $30.00  for  the  first  claim, 
and  $20.00  for  each  additional  claim  is  required  for  office  expenses. 

The  Surveyor  General  will  then  issue  an  order  for  the  survey  naming 
therein  the  Mineral  Surveyor.  The  order  is  sent  direct  to  the  Mineral 
Surveyor  who  in  turn  makes  the  necessary  surveys  as  prescribed  in  the 
Manual  of  Instructions  for  the  Survey  of  Mineral  Lands. 

A Mineral  Surveyor  cannot  act  as  an  attorney  and  a Mineral  Surveyor 
at  the  same  time.  After  the  survey  is  completed,  and  the  necessary  re- 
turns forwarded  to  the  Surveyor  General,  including  reports,  plat,  and 
field  notes,  it  is  checked,  and  if  approved,  the  Surveyor  is  so  notified, 
and  his  duty  in  connection  with  the  survey  thereby  ceases. 


24  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

One  plat  and  one  copy  of  the  original  field  notes  are  prepared  by  the 
Surveyor  General.  The  plat  is  sent  to  the  General  Land  Office  where  I 
ten  lithographic  copies  are  made  from  the  original.  One  copy  is  given 
to  the  claimant  for  posting  on  the  claim  together  with  a notice  of  in- 
tention to  apply  for  patent ; seven  copies  and  the  original  field  notes 
are  retained  by  the  Surveyor  General ; one  copy,  and  a copy  of  the  field 
notes  are  sent  to  the  claimant  to  be  filed  by  him  with  the  Register  of  the 
Land  Office  to  be  finally  transmitted  by  that  officer,  with  other  papers  in 
the  case,  to  the  General  Land  Office;  and  one  copy  is  to  be  sent  by 
the  Surveyor  General  to  the  Register  of  the  proper  land  district,  to  be 
retained  on  his  files  for  future  reference.  Copies  of  all  plats  be- 
ginning with  Survey  No.  9200  may  be  purchased  from  the  Surveyor 
General  for  fifty  cents  each. 

The  claimant  must  post  a copy  of  the  plat,  with  a notice  of  intention 
to  apply  for  patent,  on  the  claim  before  filing  his  application  for  patent. 

At  least  two  disinterested  witneses  must  sign  an  affidavit  that  the 
notice  and  plat  have  been  posted  on  the  claim.  After  the  application  for 
patent  has  been  published  for  a period  of  sixty  days,  and  after  the 
necessary  plats,  notes,  and  affidavits,  have  been  properly  posted  and 
filed,  and  upon  payment  of  five  dollars  per  acre  for  lode  claims,  and  two 
dollars  and  fifty  cents  for  placer  claims,  a register’s  certificate  will  be 
issued  to  the  applicant,  provided,  that  no  contests  are  filed  against  the 
claim  and  fraud  has  not  been  committed. 

Following  is  Section  2325  of  the  Revised  Statutes,  regarding  the  patent- 
ing of  mineral  lands : 

“A  patent  for  any  land  claimed  and  located  for  valuable  deposits  may 
be  obtained  in  the  following  manner : Any  person,  association,  or  cor- 

poration authorized  to  locate  a claim  under  this  chapter,  having  claimed 
and  located  a piece  of  land  for  such  purposes,  who  has,  or  have,  complied 
with  the  terms  of  this  chapter,  may  file  in  the  proper  land  office  an 
application  for  a patent  under  oath,  showing  such  compliance,  together 
with  a plat  and  field  notes  of  the  claim  or  claims  in  common,  made  by 
or  under  the  direction  of  the  United  States  surveyor-general,  showing 
accurately  the  boundaries  of  the  claim  or  claims,  which  shall  be  distinctly 
marked  by  monuments  on  the  ground,  and  shall  post  a copy  of  such 
plat,  together  with  a notice  of  such  application  for  a patent,  in  a con- 
spicuous place  on  the  land  embraced  in  such  plat  previous  to  the  filing 
of  the  application  for  a patent,  and  shall  file  an  affidavit  of  at  least 
two  persons  that  such  notice  has  been  duly  posted,  and  shall  file  a copy 
of  the  notice  in  such  land  office,  and  shall  thereupon  be  entitled  to  a 
patent  for  the  land;  in  the  manner  following : The  register  of  the  land 

office,  upon  the  filing  of  such  application,  plat,  field  notes,  notices,  and 
affidavits,  shall  publish  a notice  that  such  application  has  been  made, 
for  the  period  of  sixty  days,  in  a newspaper  to  be  by  him  designated  as 
published  nearest  to  such  claim ; and  he  shall  also  post  such  notice  in 
his  office  for  the  same  period.  The  claimant  at  the  time  of  filing  this 
application,  or  at  any  time  thereafter,  wdthin  the  sixty  days  of  publica- 
tion, shall  file  with  the  register  a certificate  of  the  United  States 
surveyor-general  that  five  hundred  dollars’  worth  of  labor  has  been  ex- 
pended or  improvements  made  upon  the  claim  by  himself  or  grantors; 
that  the  plat  is  correct,  with  such  further  description  by  such  reference 
to  natural  objects  or  permanent  monuments  as  shall  identify  the  claim, 
and  furnish  an  accurate  description,  to  be  incorporated  in  the  patent. 

At  the  expiration  of  the  sixty  days  of  publication,  the  claimant  shall 
file  his  affidavit,  showing  that  the  plat  and  notice  have  been  posted  in 
a conspicuous  place  on  the  claim  during  such  period  of  publication.  If 


LOCATION,  REPRESENTATION,  PATENTING  MINERAL  LANDS  25 

no  adverse  claim  shall  have  been  filed  with  the  register  and  the  receiver 
of  the  proper  land  office  at  the  expiration  of  sixty  days  of  publication, 
it  shall  be  assumed  that  the  applicant  is  entitled  to  a patent,  upon  the 
payment  to  the  proper  officer  of  five  dollars  per  acre,  and  that  no 
adverse  claim  exists ; and  thereafter  no  objection  from  third  parties  to 
the  issuance  of  a patent  shall  be  heard,  except  it  be  shown  that  the 
applicant  has  failed  to  comply  with  the  terms  of  this  chapter.  This 
section  was  amended  January  22,  1880,  as  follows 

When  Made  by  Authorized  Agent: 

“That  section  twenty-three  hundred  and  twenty-five  of  the  Revised 
Statutes  of  the  United  States  be  amended  by  adding  thereto  the  follow- 
ing words : ‘Provided,  that  where  the  claimant  for  a patent  is  not  a 

resident  of  or  within  the  land  district  wherein  the  vein,  lode,  ledge,  or 
deposit  sought  to  be  patented  is  located,  the  application  for  patent  and 
the  affidavits  required  to  be  made  in  this  section  by  the  claimant  for 
such  patent  may  be  made  by  his,  her,  or  its  authorized  agent,  where  said 
agent  is  conversant  with  the  facts  sought  to  be  established  by  said 
affidavits : And  Provided,  That  this  section  shall  apply  to  all  applica- 

tions now  nending  for  patents  to  mineral  lands.’  ” 

Form  for  Application  to  U.  S.  Surveyor  General  for  Surveys  of  Mining 
Claims : 


: 19... 

United  States  Surveyor-General, 

Sir:  , claimant....  hereby  make....  applica- 

tion for  an  official  survey,  under  the  provisions  of  Chapter  6,  Title  32, 
of  the  Revised  Statutes  of  the  United  States,  and  regulations  and 

instructions  thereunder,  of  the  mining  claim  known  as  the , 

situated  in mining  district,  

county in  section.... , township  No Range  No 

Said  claim  is  based  upon  a valid  location  made  on  , 

19 , and  duly  recorded  on  19 , and  is 

fully  described  in  the  duly  certified  copy  of  the  record  of  the  location 
certificate,  filed  herewith.  Said  certificate  contains  the  name  of  the 
locator,  the  date  of  location,  and  such  a definite  description  of  the  claim 
by  reference  to  natural  objects  or  permanent  monuments  as  will  identify 
the  claim,  and  said  location  has  been  distinctly  marked  by  monuments 

on  the  ground,  so  that  its  boundaries  can  be  readily  traced 

request  that  you  send an  estimate  of  the  amount  required 

to  defray  the  expenses  of  platting  and  other  work  in  your  office,  required 

under  the  regulations,  that  may  make  proper  deposit 

therefore,  and  that  thereupon  you  will  cause  the  survey  to  be  made  by 

, United  States  mineral  surveyor,  and  proper 

action  to  be  taken  thereon  by  your  office,  as  required  by  the  United  States 
mining  laws  and  regulations  thereunder. 

, Claimant. 

P.  O.  Address 


County. 


26  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

Adverse  Claim:  Section  2326  Revised  Statutes. 

“Where  an  adverse  claim  is  filed  during  the  period  of  publication,  it 
shall  be  upon  oath  of  the  person  or  persons  making  the  same,  and  shall 
show  the  nature,  boundaries,  and  extent  of  such  adverse  claim,  and  all 
proceedings,  except  the  publication  of  notice  and  making  and  filing  of 
the  affidavit  thereof,  shall  be  stayed  until  the  controversy  shall  have 
been  settled  or  decided  by  a court  of  competent  jurisdiction,  or  the  adverse 
claim  waived.  It  shall  be  the  duty  of  the  adverse  claimant,  within  thirty 
days  after  filing  his  claim,  to  commence  proceedings  in  a court  of  com- 
petent jurisdiction,  to  determine  the  question  of  the  right  of  possession, 
and  prosecute  the  same  with  reasonable  diligence  to  final  judgment ; and 
a failure  so  to  do  shall  be  a waiver  of  his  adverse  claim.  After  such 
judgment  shall  have  been  rendered,  the  party  entitled  to  the  possession 
of  the  claim,  or  any  portion  thereof,  may  without  giving  further  notice, 
file  a certified  copy  of  the  judgment  roil  with  the  register  of  the  land 
office,  together  with  the  certificates  of  the  surveyor-general  that  the 
requisite  amount  of  labor  has  been  expended  or  improvements  made 
thereon,  and  the  description  required  in  other  cases,  and  shall  pay  to 
the  receiver  five  dollars  per  acre  for  his  claim,  together  with  the  proper 
fees,  whereupon  the  whole  proceedings  and  the  judgment  roll  shall  be 
certified- by  the  register  to  the  Commissioner  of  the  General  Land  Office, 
and  a patent  shall  issue  thereon  for  the  claim,  or  such  portion  thereof 
as  the  applicant  shall  appear,  from  the  decision  of  the  court,  to  rightly 
possess.  If  it  appears  from  the  decision  of  the  court  that  several  parties 
are  entitled  to  separate  and  different  portions  of  the  claim,  each  party 
may  pay  for  his  portion  of  the  claim  with  the  proper  fees,  and  file  the 
certificate  and  description  by  the  surveyor-general,  whereupon  the  register 
shall  certify  the  proceedings  and  judgment  roll  to  the  Commissioner  of  the 
General  Land  Office,  as  in  the  preceding  case,  and  patents  shall  issue 
to  the  several  parties  according  to  their  respective  rights.  Nothing  herein 
contained  shall  be  construed  to  prevent  the  alienation  of  a title  conveyed 
by  a patent  for  a mining  claim  to  any  person  whatever.” 

This  section  was  amended  by  Act  of  March  3,  1881,  as  follows : 

“That  if,  in  any  action  brought  pursuant  to  section  twenty-three 
hundred  and  twenty-six  of  the  Revised  Statutes,  title  to  the  ground  in 
controversy  shall  not  be  established  by  eithey  party,  the  jury  shall  so 
find,  and  judgment  shall  be  entered  according  to  the  verdict.  In  such 
case  costs  shall  not  be  allowed  to  either  party,  and  the  claimant  shall 
not  proceed  in  the  land  office  or  be  entitled  to  a patent  for  the  ground 
in  controversy  until  he  shall  have  perfected  his  title.” 

This  section  was  further  amended  by  Act  of  April  26,  1882,  as  follows : 

“That  the  adverse  claim  required  by  section  twenty-three  hundred  and 
twenty-six  of  the  Revised  Statutes  may  be  verified  by  the  oath  of  any 
duly  authorized  agent  or  attorney  in  fact  of  the  adverse  claimant 
cognizant  of  the  facts  stated ; and  the  adverse  claimant,  if  residing  at 
the  time  being  beyond  the  limits  of  the  district  wherein  the  claim  is 
situated,  may  make  oath  to  the  adverse  claim  before  the  clerk  of  any 
court  of  record  of  the  United  States  or  the  State  or  Territory  where  the 
adverse  claimant  may  then  be,  or  before  any  notary  public  of  such  State 
or  Territory.” 

When  there  is  any  dispute  over  the  rights  of  possession  of  the  land  it 
is  necessary  for  the  adverse  claimant  to  file  his  adverse  claim  during  the 
sixty  day  period  of  publication,  and  commence  proceedings  to  determine 
the  question  of  rights  of  possession  within  thirty  days  thereafter,  but  if 
no  adverse  claim  is  filed  before  the  time  for  publication  expires,  applica- 
tion is  then  made  for  title  to  the  ground,  such  application  being 
accompanied  by  a sum  equivalent  to  $5.00  per  acre  or  fraction  thereof 
for  lode  claims,  and  $2.50  per  acre  or  fraction  thereof  for  placer  claims, 


LOCATION,  REPRESENTATION,  PATENTING  MINERAL  LANDS  27 


for  which  the  Register  will  issue  a duplicate  receipt.  The  returns  of 
the  survey  with  the  required  approval  of  the  Surveyor-General  are  then 
furnished  to  the  Commissioner  of  the  General  Land  Office  in  Washington, 
D.  C.,  who  upon  approving  the  application,  will  issue  the  patent,  w^hich 
is  a conveyance  from  the  United  States  Government. 

After  the  purchase  price  of  the  land  has  been  accepted  by  the  Land 
Office,  for  which  a Register’s  certificate  has  been  issued,  no  annual  work 
need  be  performed. 

After  obtaining  patent  the  owner  may  sell,  transfer,  or  otherwise 
dispose  of  said  claim  or  claims  in  any  manner  desired.  Upon  receiving 
title  from  the  Government  the  patentee  is  granted  the  exclusive  right  of 
possession  and  enjoyment  of  all  the  surface  included  within  his  claim, 
and  of  all  veins,  lodes,  and  ledges  throughout  their  entire  depth,  the  top 
or  apex  of  which  lies  inside  of  his  surface  boundaries,  and  he  may  follow 
such  veins,  lodes,  or  ledges,  downward  indefinitely  even  though  it  may 
be  necessary  to  pass  outside  of  the  vertical  boundaries  of  his  side  lines. 
Such  rights  as  granted  by  the  Government,  can  only  apply  to  such  portions 
of  the  veins  that  lie  between  vertical  planes  passing  through  the  end  lines 
of  the  claim  which  must  be  parallel.  These  vertical  planes  are  indefinite 
in  size.  (See  Section  2322,  Revised  Statutes,  page  29). 

Such  rights  are  known  as  “Extralateral  Rights”  and  due  to  the  many 
varied  opinions  and  complications  pertaining  to  the  same  it  would  not 
be  proper  nor  possible  to  discuss  the  same,  even  briefly,  within  the  limits 
of  this  bulletin. 

Following  are  sketches  illustrating  what  has  been  said  above. 

Figure  5 shows  an  ideal  claim  with  two  veins  dipping  in  the  same  direc- 
tion and  figure  6 shows  a section  through  AA  in  which  an  end  view  is 
seen. 

The  owner  according  to  Section  2322,  of  the  Revised  Statutes,  owns 
both  veins,  and  can  follow  each,  indefinitely  in  depth,  beyond  the  vertical 
plane  of  the  side  lines  passing  through  the  corners  1 and  4 as  shown  in 
figure  5.  The  owner’s  rights  to  follow  and  mine  the  vein  beyond  the  side 


28  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


lines  as  at  B in  figure  6,  are  known  as  “Extraside  Rights”  or  “Extralateral 
Rights.”  “C,”  figure  6,  is  the  apex  or  top  of  the  vein.  In  order  to  have 
any  “Extralateral  Rights”  it  is  necessary  to  have  the  top  or  apex  of  the 
vein  within  the  limits  of  one’s  claim,  and  the  vein  passing  through 
at  least  one  end  line. 

Apex  should  not  be  confused  with  outcrop  as  the  latter  may  or  may 
not  be  the  apex.  See  figure  7. 

AA  is  an  outcrop,  that  is,  where  the  vein  comes  to  the  surface,  while 
“B”  is  the  apex  and  an  outcrop. 

An  outcrop  is  the  exposed  edge  of  the  vein  at  the  surface. 

The  apex  of  a vein  is  the  top  edge  of  the  vein  along  its  entire  course. 
It  may  appear  at  the  surface,  or  in  the  case  of  a blind  vein,  it  may  be 
at  a considerable  distance  from  the  surface. 


LOCATION,  REPRESENTATION,  PATENTING  MINERAL  LANDS  29 


In  figure  8,  the  outcrop  is  shown  at  D and  the  apex  at  E. 

The  claimant  may  by  his  extralateral  rights,  mine  all  ore  in  the  main 
vein  (figure  5)  between  the  two  vetrical  parallel  planes  passing  through 
the  end  lines  1-2  and  3-4,  and  all  ore  from  the  secondary  vein  between 
two  parallel  vertical  planes  passing  through  corners  3-4  and  the  point 
where  the  secondary  veins  crosses  the  side  lines  2-3. 

Revised  Statutes  Pertaining  to  Rights  of  Possession  and  Extralateral 
Rights : 

“Sec.  2322.  The  locators  of  all  mining  locations  heretofore  made,  or 
which  shall  hereafter  be  made,  or  any  mineral  vein,  lode,  or  ledge, 
situated  on  the  public  domain,  their  heirs  and  assigns,  where  no  adverse 
claim  exists  on  the  tenth  day  of  May,  eighteen  hundred  and  seventy-two, 
so  long  as  they  comply  with  the  laws  of  the  United  States  governing 
their  possessory  title,  shall  have  the  exclusive  right  of  possession  and 
enjoyment  of  all  the  surface  included  within  the  lines  of  their  locations, 
and  of  all  veins,  lodes,  and  ledges  throughout  their  entire  depth,  the  top 
or  apex  of  which  lies  inside  of  such  surface  lines  extended  downward 
vertically,  although  such  veins,  lodes,  or  ledges  may  so  far  depart  from 
a perpendicular  in  their  course  downward  as  to  extend  outside  the 
vertical  planes  drawn  downward  as  above  described,  through  the  end 
lines  of  their  location,  so  continued  in  their  own  direction  that  such 
planes  will  intersect  such  exterior  parts  of  such  veins  or  ledges.  And 
nothing  in  this  section  shall  authorize  the  locator  or  possessor  of  a vein 
or  lode  which  extends  in  its  downward  course  beyond  the  vertical  lines 
of  his  claim  to  enter  upon  the  surface  of  a claim  owned  or  possessed 
by  another.” 

“Sec.  2336  R.  S.  Where  twTo  or  more  veins  intersect  or  cross  each 
other,  priority  of  title  shall  govern,  and  such  prior  location  shall  be 
entitled  to  all  ore  or  mineral  contained  within  the  space  of  intersection ; 
but  the  subsequent  location  shall  have  the  right  of  way  through  the 
space  of  intersection  for  the  purposes  of  the  convenient  working  of  the 
mine.  And  where  two  or  more  veins  unite,  the  oldest  and  prior  location 
shall  take  the  vein  below  the  point  of  union,  including  all  the  space  of 
intersection. — Act  of  May  10,  1872.” 

PLACER  LOCATIONS. 

A placer  claim,  that  is,  a claim  containing  mineral  deposits  in  a 
loose  state  or  not  in  place,  may  be  located  in  the  same  manner  as  a 
lode  claim.  See  page  12.  Mineral  deposits  which  may  be  located  as 
placer  deposits  are  mentioned  on  page  10. 

The  area  of  one  location  may  vary  from  twenty  acres  to  one  hundred 
and  sixty  acres,  depending  upon  the  number  of  locators.  A corporation 


30  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

or  any  qualified  locator  may  not  locate  more  than  twenty  acres  in  one 
location.  A claim  containing  one  hundred  and  sixty  acres  may  be  located 
by  an  association  of  eight  locators. 

One  discovery  of  mineral  is  necessary  for  each  location,  whether  it 
is  a location  of  twenty  acres  by  an  individual  or  one  of  one  hundred  and 
sixty  acres  by  an  association  of  persons.  A location  having  an  area  in 
excess  of  that  allowed  by  the  law,  is  void  only  as  to  the  excess. 

In  Montana  it  is  necessary  to  make  a discovery,  post  a notice  of  location, 
erect  corners,  perform  the  discovery  work,  record  the  certificate  of  loca- 
tion, and  perform  the  necessary  annual  labor  for  placer  claims  in  the  same 
manner  as  for  lode  claims. 

The  following  are  the  sections  of  the  Revised  Statutes  of  the  United 
States  relating  to  placers : 

Section  2329,  Revised  Statutes : “Claims  usually  ‘called  ‘placers’  in- 

cluding all  forms  of  deposit,  excepting  veins  of  quartz,  or  other  rock  in 
place,  shall  be  subject  to  entry  and  patent,  under  like  circumstances  and 
conditions,  and  upon  similar  proceedings,  as  are  provided  for  vein  or 
lode  claims;  but  wThere  the  lands  have  been  previously  surveyed  by  the 
United  States,  the  entry  in  its  exterior  limits  shall  conform  to  the  legal 
subdivision  of  the  public  lands.”  (Act  of  July  9,  1870). 

Section  2330.  “Legal  subdivisions  of  forty  acres  may  be  subdivided 
into  ten-acre  tracts ; and  two  or  more  persons,  or  associations  of  persons, 
having  contiguous  claims  of  any  size,  although  such  claims  may  be  less 
than  ten  acres  each,  may  make  joint  entry  thereof;  but  no  location  of  a 
placer  claim,  made  after  the  ninth  day  of  July,  eighteen  hundred  and 
seventy,  shall  exceed  one  hundred  and  sixty  acres  for  any  one  person 
or  association  of  persons,  which  location  shall  conform  to  the  United 
States  surveys ; and  nothing  in  this  section  contained  shall  defeat  or 
impair  any  bona  fide  preemption  or  homestead  claim  upon  agricultural 
lands,  or  authorize  the  sale  of  the  improvements  of  any  bona  fide  settler 
to  any  purchases.” 

Section  2331.  “Where  placer  claims  are  upon  surveyed  lands,  and 
conform  to  legal  subdivisions,  no  further  survey  or  plat  shall  be  required, 
and  all  placer-mining  claims  located  after  the  tenth  day  of  May,  eighteen 
hundred  and  seventy-two,  shall  conform  as  near  as  practicable  with  the 
United  States  system  of  public-lands  surveys,  and  the  rectangular  sub- 
divisions of  such  surveys,  and  no  such  location  shall  include  more  than 
twenty  acres  for  each  individual  claimant;  but  wThere  placer  claims 
cannot  be  conformed  to  legal  subdivisions,  survey  and  plat  shall  be  made 
as  on  unsurveyed  lands ; arid  where  by  segregation  of  mineral  lands  in 
any  legal  subdivision  a quantity  of  agricultural  land  less  than  forty  acres 
remains,  such  fractional  portion  of  agricultural  land  may  be  entered  by 
any  party  qualified  by  law,  for  homestead  or  preemption  purposes.”  (Act 
of  May  10,  1872). 

A placer  claim  must  be  rectangular  or  square  in  shape,  and  it  must 
conform  to  the  subdivisions  of  the  public  land,  that  is,  the  boundaries 
must  run  as  nearly  as  practicable,  north  and  south,  or  east  and  west 
whether  on  surveyed  or  unsurveyed  land. 

No  location  may  exceed  twenty  acres  for  one  locator.  A location  greater 
than  twTenty  acres  but  not  in  excess  of  forty  acres  must  be  made  by  two 
locators,  one  greater  than  sixty  acres  but  not  in  excess  of  eighty  acres 
must  be  made  by  four  locators,  and  so  on. 

“Gulch  Placers”  may  be  located  with  the  boundaries  somewhat  irregu- 
lar, but  if  possible,  the  boundaries  should  run  north  and  south,  and  east 
and  west,  as  stated  above. 


location,  representation,  PATENTING  MINERAL  LANDS  31 


All  locations  should  be  compact  and  regular  in  form.  Long  narrow 
locations  or  one  grossly  irregular  will  not  be  permitted. 


Figure  9 illustrates  bow  public  lands  may  be  subdivided  in  order  to 
take  up  various  tracts  as  placer  claims. 

Form  for  Placer  Location: 

NOTICE  OF  PLACER  LOCATION. 

Notic„e  is  hereby  given  that  the  undersigned  locator....  and  claimant— 

ba on  this day  of , A.  D.  19 

discovered  a deposit  of  gold,  or  other  valuable  deposits,  having  a com- 
mercial value,  and  do hereby  locate  and  claim  same,  which  shall  be 

known  as  Placer  Mining  Claim,  and  did  on  the  same 

day  post  this  notice  at  the  point  of  discovery. 

The  dimensions  of  this  claim  are  feet  in  a 

direction,  and  feet  in  a direction  from  the 

point  of  discovery,  by  feet  on  each  side  of  middle  of  claim, 

containing  acres. 

Witnesses  : Locators  and  claimants : 


Note : For  each  multiple  of  twenty  acres  in  the  located  area  or  claim, 

there  should  be  one  qualified  locator  who  must  sign  the  notice  of  location. 

This  notice  of  location  must  be  posted  on  the  claim  at  or  near  the  point 
of  discovery. 


32 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


Form  for  Certificate  of  Placer  Location: 

CERTIFICATE  OF  LOCATION 

of  the 


Placer  Mining  Claim. 

Know  All  Men  by  These  Presents,  That  the  undersigned,  each  of  whom 
is  a citizen  of  the  United  States,  or  has  declared  his  intention  to  become 

such,  did,  on  the day  of , 19 , discover 

a placer  deposit  bearing  gold,  and  other 

minerals  having  a commercial  value,  and  on  the  same  day  did  locate  and 

claim  the  same  as  the Placer  Mining  Claim, 

by  posting  a notice  of  location  conspicuously  at  the  point  of  said  discov- 
ery, containing  the  name  of  said  claim,  the  name....  of  the  undersigned  as 
locator....,  the  date  of  said  location,  and  the  approximate  dimensions  of 
such  claim  intended  to  be  appropriated. 

This  claim  is  situated  in Mining  District 


(unorganized),  in  the  County  of , State  of 

Montana.  The  adjoining  claims  are  as  follows,  to-wit: 

On  the  North , the Claim; 

On  the  East,  the . Claim  ; 

On  the  South , the Claim  ; 

On  the  West,  the Claim  ; 

Measured  from  the  discovery of  this  claim 

as  a starting  point,  the  following  natural  objects  and  permanent  monu- 
ments are  distant  as  follows,  to-wit : . is 

distant feet  in  a direction ; 

is  distant  feet  in  a direction. 


Subsequent  to  the  date  of  said  location,  to-wit,  on  the day 

of  , 19 , the  undersigned  did  distinctly 

mark  said  location  on  the  ground  so  that  its  boundaries  could  be  readily 
traced,  in  the  following  manner,  to-wit : 


Beginning  at. 


Corner  No.  1,  which  is  a. 


and  which  is  distant feet  in  a 

direction  from  the  point  of  discovery,  and  running  thence 

First  Course  : Direction, distance feet, 

to Corner  No,  2,  which  is  a 


Second  Course  : Direction,  , 

to Corner  No.  3,  which  is  a 


....  and  running  thence 
distance feet, 


LOCATION,  REPRESENTATION,  PATENTING  MINERAL  LANDS  33 


.. . . and  running  thence 

Third  Course  : Direction, , distance feet, 

to Corner  No.  4,  which  is  a 


and  running  thence 

Fourth  Course:  Direction, , distance feet; 


to  Corner  No.  1,  the  place  of  beginning. 

Within  sixty  days  after  posting  said  notice  of  location  the  under- 
signed performed  the  following  discovery  work,  to-wit : 

At  the  point  of  discovery  dug  a .of  the 

following  dimensions,  to-wit : 


constituting  in  all cubic  feet  of  excavation,  and  said 

work  has  disclosed  at  the  point  of  discovery  a valuable  deposit  of 


The  undivided  interest  in  the  above  described  location,  claimed  by  each 
of  the  undersigned,  is  indicated  by  the  fraction  set  after  each  name. 


STATE  OF  MONTANA, 

> ss. 

County  of | 


Locator....  and  Claimant. 


says : That....he....is 

claimant....  whose  name. 


being  duly  sworn  on  oath 

the  locator....  and 

signed  to  the  foregoing 


34 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


Certificate  of  Location ; that  —.he... .has read  the  said 

Certificate,  and  knows  the  contents  thereof,  and  that  the  matters  and 
things  therein  stated  are  true  of  his  own  knowledge. 


Subscribed  and  sworn  to,  before  me  this day  of. 

A.  D.,  19 


Notary  Public  in  and  for County,  State  of  Montana. 

The  locators  or  claimants  according  to  the  state  laws  of  Montana,  may 
at  their  option  set  forth  in  the  certificate  of  location  a description  of  the 
discovery  work,  the  corner  monuments  and  markings  thereon,  and  any 
other  facts  showing  a compliance  with  the  provision  of  the  law.  The 
certificate  of  location  must  be  verified  as  in  the  case  of  a lode  claim 
by  some  one  of  the  locators  or  by  an  authorized  agent.  (See  page  17). 

Discovery  Work  and  Annual  Labor: 

The  same  amount  of  discovery  work  is  required  for  a placer  claim  as 
a lode  claim,  that  is,  the  excavation  of  at  least  150  cubic  feet  of  material 
in  which  the  mineral  deposit  has  been  disclosed.  (See  Lode  Claim,  Page 
17). 

The  annual  labor,  which  is  the  same  as  a lode  claim  must  be  performed 
in  order  to  hold  the  placer  location  whether  it  be  for  a location  of  twenty 
acres  or  for  a location  by  an  association  of  eight  locators  for  one  hundred 
sixty  acres. 

Patenting  Placer  Claim: 

A patent  for  a placer  claim  may  be  applied  for  in  the  same  manner 
as  a lode  claim.  (See  Section  2325,  Revised  Statutes.  Page  24.) 

Vein  or  Lode  Within  Placer  Claim: 

“Sec.  2333.  Where  the  same  person,  association,  or  corporation  is  in 
possession  of  a placer*  claim,  and  also  a vein  or  lode  included  within 
the  boundaries  thereof,  application  shall  be  made  for  a patent  for  the 
placer  claim,  with  the  statement  that  it  includes  such  vein  or  lode,  and 
in  such  case  a patent  shall  issue  for  the  placer  claim,  subject  to  the  pro- 
visions of  this  chapter,  including  such  vein  or  lode,  upon  the  payment 
of  five  dollars  per  acre  for  such  vein  or  lode  claim  and  twenty-five  feet 
of  surface  on  each  side  thereof.  The  remainder  of  the  placer  claim,  or 
any  placer  claim  not  embracing  any  vein  or  lode  claim  shall  be  paid  for 
at  the  rate  of  two  dollars  and  fifty  cents  per  acre,  together  with  all 
costs  of  proceedings ; and  where  a vein  or  lode,  such  as  described  in 
section  twenty-three  hundred  and  twenty,  is  known  to  exist  within  the 
boundaries  of  a placer  claim  which  does  not  include  an  application  for 
the  vein  or  lode  claim  shall  be  construed  as  a conclusive  declaration 
that  the  claimant  of  the  placer  claim  has  no  right  of  possession  of  the 
vein  or  lode  claim ; but  where  the  existence  of  the  vein  or  lode  in  a 
placer  claim  is  not  known,  a patent  for  the  placer  claim  shall  convey 
all  valuable  mineral  and  other  deposits  within  the  boundaries  thereof.” 

No  person  may  legally  prospect  for  a vein  or  lode,  or  locate  a vein,  if 
discovered,  within  the  boundaries  of  a valid  placer  location  without  the 
consent  of  the  placer  claimant. 

If  a vein  is  discovered  within  the  boundaries  of  a valid  placer  location 
by  the  placer  claimant  it  will  not  be  necessary  to  locate  the  vein  as  a 


LOCATION,  REPRESENTATION,  PATENTING  MINERAL  LANDS  35 


regular  lode  location,  but  when  an  application  is  made  for  a patent  for 
the  placer  claim,  the  fact  that  the  vein  or  lode  exists  within  its  boundaries 
should  be  stated,  and  an  application  for  a patent  for  the  vein  or  lode 
should  then  be  included  with  the  placer  application.  If  a vein  is  known 
to  exist,  and  it  is  not  so  stated  in  the  application,  the  placer  claimant  will 
have  no  rights  to  the  vein.  The  title  to  a vein  found  after  the  placer 
patent  is  issued,  remains  with  the  owner  of  the  claim.  No  extralateral 
rights  are  granted  for  such  a vein. 

When  a valuable  vein  is  discovered  within  the  lines  of  a placer  loca- 
tion before  an  application  is  made  for  patent,  it  would  be  advisable  for 
the  placer  claimant  to  locate  the  vein  by  making  a regular  lode  location 
covering  a tract  twenty-five  feet  on  each  side  of  the  vein,  and 
not  to  exceed  fifteen  hundred  feet  in  length,  in  order  to  avoid  any 
possible  future  disputes.  When  such  a vein  is  properly  located  and 
patented,  extralateral  rights  are  granted,  otherwise  no  extralateral  rights 
are  attached  to  veins  found  within  the  placer  location. 

Placer  claims  must  be  paid  for  at  the  rate  of  two  dollars  and  fifty 
cents  per  acre  or  fraction  thereof  provided  they  do  not  contain  any  veins 
or  lodes.  In  case  of  a known  vein  the  regular  price  of  five  dollars  per 
acre  for  a strip  of  ground  twenty-five  feet  on  each  side  of  the  vein  is 
required. 

When  forty-acre  tracts  are  subdivided  into  ten-acre  tracts,  they  must 
be  in  square  form,  and  with  the  boundaries  of  the  tracts  running  north 
and  south,  and  east  and  west.  Entry  for  such  ten-acre  tracts  may  be 
made  after  the  usual  proceedings  without  any  additional  surveys  or 
plats,  when  on  surveyed  government  land. 

A tract  of  ten  acres,  as  in  “A,”  figure  9,  page  31,  may  be  described  as 
the  N.  W.  *4  of  the  N.  E.  )4  of  the  N.  E.  % of  the  section  in  wThich 
the  claim  is  located. 

Forfeiture,  Abandonment,  Relocation,  Co-Owners  of  Placer  Claims: 

The  rules  relating  to  forfeiture,  abandonment,  relocation,  and  rights 
of  co-owners  apply  in  the  same  manner  for  placer  locations  as  for  lode 
locations.  (See  pages  21  and  22). 

Tunnel  Claims : Location. 

(See  Section  2323,  Revised  Statutes,  page  10). 

After  a tunnel  has  been  started  and  enters  cover,  a location  notice  for 
the  tunnel  is  required  to  be  posted  at  or  near  the  mouth  of  the  tunnel. 
This  notice  should  contain  (1)  the  name  or  names  of  the  locator  or 
locators  claiming  the  tunnel  right,  (2)  the  course  and  direction  of  the 
proposed  tunnel,  (3)  the  height  and  width  of  the  tunnel  and  (4)  the 
course  and  distance  from  the  face  to  some  natural  and  permanent  objects 
in  the  vicinity.  When  the  notice  is  posted,  the  claimant  should  establish 
the  boundary  lines  by  stakes  or  monuments  placed  along  such  lines  at 
proper  interval,  and  extending  to  the  end  of  the  proposed  tunnel,  that  is, 
3,000  feet  from  the  first  working  face.  These  lines  are  so  staked  that 
there  will  exist  definite  boundaries  within  which  prospecting  or  locating 


36  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

of  any  previously  unknown  veins  or  lodes  is  prohibited  while  work  on  the 
tunnel  is  being  prosecuted  with  reasonable  diligence.  (L.  O.  Reg.). 

A copy  of  the  tunnel  location  notice  must  be  filed  with  the  County 
Clerk  and  Recorder,  to  which  notice  must  be  attached  a sworn  state- 
ment or  declaration  of  the  owners,  claimants,  or  projectors  of  such 
tunnel,  setting  forth  the  facts  in  the  case;  stating  the  amount  expended 
by  themselves  and  their  predecessors  in  interest  in  prosecuting  the  work 
thereon ; the  extent  of  the  work  performed,  and  that  it  is  bona  fide 
their  intention  to  prosecute  work  on  the  tunnel  so  located  and  described 
with  reasonable  diligence  for  the  development  of  a vein  or  lode  or  for 
the  discovery  of  mines,  or  both.  This  notice  of  location  must  be  duly 
recorded,  and,  with  the  said  sworn  statement  attached,  kept  on  the 
Recorder’s  files  for  future  reference. 

Work  must  be  performed  in  the  tunnel  with  reasonable  diligence.  If 
the  work  in  the  tunnel  is  not  performed  for  a period  of  six  months,  the 
right  to  all  undiscovered  veins  on  the  line  of  the  tunnel  shall  be  con- 
sidered as  abandoned,  and  other  locators  may  stake  out  lode  claims  on 
the  surface  which  may  contain  such  undiscovered  veins. 

The  laws  of  Montana  do  not  make  known  any  requirements  in  regard 
to  the  location  of  a tunnel  claim  and  the  foregoing  have  been  taken, 
from  Land  Office  Regulations. 

No  Patent  for  Tunnel  Claim: 

A tunnel  claim  cannot  be  patented,  but  all  veins  or  lodes  that  are  cut 
while  driving  the  tunnel  may  be  located  by  staking  out  the  boundaries 
of  a lode  claim  as  prescribed  by  the  laws  for  a regular  lode  location,  and 
such  lode  claims  may  then  be  patented  in  the  usual  way.  Money  spent  in 
driving  the  tunnel  may  be  counted  as  annual  labor  in  making  application 
for  patent  for  such  lode  claims  as  include  the  veins  and  lodes  as  cut  by 
the  tunnel. 

Labor  on  Tunnel  Claim: 

By  an  Act  of  Congress,  approved  February  11,  1875,  Section  2324,  of 
the  Revised  Statutes,  wras  amended,  so  that  where  a person  or  company 
has  driven  a tunnel  for  the  purpose  of  developing  a lode  or  lodes,  the 
money  so  expended  in  the  tunnel  shall  be  taken  and  considered  as  ex- 
pended on  such  lode  or  lodes,  and  that  the  owner  or  claimant  shall  not 
be  required  to  perform  any  work  on  the  surface  of  such  lode  or  lodes 
in  order  to  hold  the  same  as  required  by  laws  pertaining  to  annual  labor. 
(See  page  20). 

Staking  Lode  Claims  on  Surface: 

The  method  for  locating  or  staking  out  a lode  claim  which  includes 
such  vein  or  lode  as  cut  by  a tunnel  right  seems  to  have  provoked 
many  different  opinions.  The  laws  of  location  do  not  state  any  definite 
point  as  to  where  the  location  corners,  or  the  discovery  on  any  claim 
should  be ; that  is,  a location  is  not  void  if  the  discovery  point  is  near 
one  end  line,  or  in  the  center  of  the  claim,  or  even  close  to  some  corner, 
and  it  would  therefore  seem  logical  and  valid  to  locate  a claim  on  either 


LOCATION,  REPRESENTATION,  PATENTING  MINERAL  LANDS  37 


side  of  the  tunnel  for  a distance  of  1500  feet  along  the  vein  and  in  any 
direction,  the  distance  to  be  measured  in  all  cases  from  the  tunnel,  or 
to  locate  1500  feet  along  such  vein  or  lode  so  that  a portion  of  the  claim 
may  lie  on  either  side  of  the  tunnel. 

Millsites:  Location  of  (See  page  11). 

Millsite  claims  may  be  located  and  recorded  in  the  same  manner  as 
other  claims  except  that  no  discovery  work  is  required.  When  a millsite 
is  located  in  connection  with  a lode  claim,  the  certificate  of  location 
shall  describe  by  appropriate  reference  such  lode  claims.  (See  location 
of  Lode  Claims,  page  12). 

Form  for  Millsite  Location: 

NOTICE  OF  MILLSITE  LOCATION. 

Notice  is  hereby  given,  that  the  undersigned  claimant....  and  owner.. . 

of  the Lode  Claim,  or Quartz 

Mill  or  Reduction  Works,  situated  in  the  County  of 

State  of  Montana,  did,  on  this day  of A.  D. 

19 , locate  five  acres  of  non-mineral  land  as  the Millsite. 

That,  the  approximate  dimensions  of  area  are feet  by feet. 

That  this  notice  was  posted  on  the  same  date  at  the 

Corner  No.  1,  from  which  the Corner  No.  2 is  approximately 

feet  in  a direction,  thence 

feet  in  a direction  to Corner  No. 

3,  thence feet  in  a direction  to 

Corner  No.  4,  thence feet  in  a direction  to 

the  place  of  beginning. 

Witnesses  : Locators  and  claimants  : 


A certificate  of  location  and  a verification  of  the  same  must  be  filed 
with  the  County  Clerk  and  Recorder  of  the  County  in  which  the  millsite 
is  located  and  must  comply  with  all  the  requirements  necessary  in  filing 
for  a lode  claim.  (See  page  18). 

The  millsite  may  be  used  in  connection  with  the  lode  claims  ap- 
purtenant thereto.  It  must  be  used  for  the  erection  of  a mill,  houses  for 
workmen,  warehouses,  or  other  mining  and  milling  purposes.  No  annual 
labor  need  be  performed  on  a millsite. 

Patenting  Millsites: 

An  application  for  patent  to  a millsite  may  be  included  in  the  applica- 
tion for  patent  for  the  lode  claim  appurtenant  thereto. 

An  application  for  patent  to  a millsite  may  also  be  made  by  an  owner 
of  a quartz  mill  or  other  reduction  plant  provided  he  does  not  own  a 


38 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


lode  claim.  He  may  make  an  application  in  the  same  manner  as  for  a 
mining  claim,  and  receive  patent  by  paying  $5.00  per  acre  or  fraction 
thereof  but  there  must  be  no  adverse  rights. 

Millsite  for  Owner  of  Patented  Claims: 

The  owner  of  a patented  lode  claim  may,  by  an  independent  applica- 
tion, secure  a millsite  if  good  faith  is  shown  in  its  use  or  occupation  in 
connection  with  the  lode  and  no  adverse  claim  exists.1 

lLand  Office  Regulations. 

Timber  and  Timber  Lands: 

By  an  Act  of  Congress,  approved  June  3,  1878,  permission  was  granted 
to  all  persons  wdio  are  residents  of  Montana,  to  cut  and  remove,  for 
building,  agricultural,  mining,  or  other  domestic  purposes,  any  timber 
or  other  trees  growing  or  being  on  the  public  lands,  which  were  mineral 
and  not  subject  to  entry  under  existing  laws  of  the  United  States,  except 
for  mineral  entry,  subject  to  such  rules  and  regulations  as  the  Secretary 
of  the  Interior  may  prescribe  for  the  protection  of  the  timber,  etc.  The 
above  provisions  do  not  extend  to  railroad  corporations. 

Timber  may  be  cut  on  unpatented  mining  claims  and  used  in  connection 
with  the  same.  Timber  on  patented  claims  may  be  cut  and  used  as  the 
owner  sees  fit. 

Timber  may  be  cut  and  used  for  mining  purposes  by  a locator  or 
claimant  of  a valid  location  on  a forest  reserve,  and  timber  may  also  be 
cut  and  removed  from  a forest  reservation  by  obtaining  permission  from 
the  local  forest  ranger  or  supervisor  and  paying  stumpage  for  the 
timber. 

The  Act  of  June  4,  1897,  provides  that:  “The  Secretary  of  the  Interior 

may  permit,  under  regulations  to  be  prescribed  by  him,  the  use  of  timber 
and  stone  found  upon  such  reservations,  free  of  charge,  by  bona  fide 
settlers,  miners,  residents,  and  prospectors  for  minerals,  for  fire  wood, 
fencing,  building,  mining,  prospecting,  and  other  domestic  purposes  as 
may  be  needed  by  such  persons  for  such  purposes ; such  timber  to  be 
used  within  the  state  or  territory  respectively  where  such  reservations 
may  be  located.” 

LEASING  ACT. 

Coal,  Phosphate,  Oil,  Oil  Shale,  Gas,  Sodium. 

The  Leasing  Act  as  approved  by  Congress  on  February  25,  1920,  is  an 
act  which  relates  to  the  mining  and  prospecting  of  mineral  deposits  of 
coal,  phosphate,  oil,  oil  shale,  gas  and  sodium. 

Lands  Affected : 

Any  land  containing  such  deposits  as  mentioned  above,  and  owned  by 
the  Government,  including  those  in  National  Forests,  and  lands  entered 
or  patented  with  such  deposits  reserved  under  laws  to  the  United  States, 
but  excluding  (1)  land  acquired  under  the  act  known  as  the  “Appalachain 
Act,”  as  approved  March  1,  1911,  and  (2)  those  in  National  Parks,  and 
(3)  lands  withdrawn  or  reserved  for  Military  or  Naval  uses  or  purposes, 


LEASING  ACT,  FEB.  25,  ,1920 


39 


and  (4)  any  land-  patented  without  such  mineral  deposits  reserved  to  the 
United  States,  and  (5)  Indian  Reservations,  are  affected  by  the  passage 
of  this  act. 

Title  to  Such  Lands : Permit  and  Lease  : 

Title  to  such  deposits  on  any  Government  lands  cannot  be  obtained. 
A permit  must  be  obtained  from  the  Secretary  of  the  Interior  to  prospect 
Government  lands  for  such  deposits,  and  a lease  must  be  obtained  to 
mine  the  deposits  after  the  same  have  been  found. 

Who  May  Receive  a Permit  or  Lease: 

Only  citizens  of  the  United  States,  association  of  citizens,  or  any  cor- 
poration, organized  under  the  laws  of  the  United  States,  or  of  any  state 
or  territory,  may  obtain  permits  or  leases. 

Cities  or  municipalities  may  obtain  a permit  to  prospect  for  coal,  oil, 
oil  shale,  or  gas,  or  a lease  to  mine  coal,  oil,  oil  shale,  or  gas,  but  not 
for  phosphate  or  sodium. 

Aliens : 

Aliens  or  citizens  of  another  country  may  not  own  any  interest  by 
stock  ownership,  stock  holding,  or  stock  control,  in  any  lease  acquired 
under  the  Leasing  Act  unless  his  country  grants  similar  or  like  privileges 
to  citizens  or  corporations  of  the  United  States.  An  alien  may  not  obtain 
a direct  holding  of  a lease.  Under  certain  conditions,  American  corpora- 
tions, with  alien  stockholders,  may  obtain  a lease. 

Number  of  Leases  Allowed: 

Only  one  coal,  phosphate,  or  sodium  lease  may  be  held  during  the  life 
of  such  lease  in  any  state,  by  any  person,  association,  or  corporation. 

Only  three  gas  or  oil  leases  in  any  one  state,  and  not  more  than  one 
lease  within  the  geologic  structure  of  the  same  producing  oil  or  gas  field 
can  be  held  by  any  one  person,  association,  or  corporation. 

Only  one  oil  shale  lease  can  be  obtained  by  any  person,  association,  or 
corporation. 

Unlawful  Rights  of  Persons  or  Corporations : 

A corporation  may  not  hold  an  interest  in  more  than  the  maximum 
number  of  leases,  either  by  direct  holding  as  a lessee,  or  indirectly  as 
a stockholder  in  other  corporations  holding  leases. 

A corporation  holding  the  maximum  number  of  leases,  for  any  kind 
of  the  above  mentioned  mineral  deposits,  may  not  hold  any  interest  in 
any  other  association,  or  corporation  having  similar  leases. 

A person  with  a direct  holding  of  a lease  of  any  kind  may  hold  an 
interest  as  a member  of  an  association,  or  as  a stockholder  of  a corpora- 
tion holding  a similar  lease  if  the  combined  area  embraced  in  the  direct 
holding  of  a lease,  and  the  area  covered  by  other  interests,  does  not  exceed 
the  maximum  number  of  acres  allowed  for  the  respective  kinds  of  mineral 
for  any  one  lessee.  Thus  an  individual  may  hold  stock  in  any  number  of 
corporations  holding  oil  or  gas  leases,  provided  his  stock  interests  do 


40  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

not  represent  a greater  acreage  than  2,560  acres  in  the  same  producing 
structure,  or  7,680  acres  in  the  same  state.  An  individual  may  hold  three 
leases  directly  for  oil  or  gas,  and  one  lease  for  coal,  sodium,  phosphate, 
or  oil  shale,  and,  at  the  same  time  hold  a stock  interest  in  a corporation 
having  leases,  provided  his  direct  and  indirect  holdings  do  not  exceed 
the  maximum  area  for  one  person.  b 

Any  interests  which  are  illegally  held  shall  be  forfeited  to  the  United 
States  by  proceedings  in  the  United  States  District  Courts. 

Interests  Acquired  by  Descent,  Will,  Judgment,  Etc,: 

Any  interest  acquired  by  descent,  will,  judgment,  or  decree  may  be 
held  for  two  years  after  its  acquisition. 

Lawful  Combined  Interests  for  Pipe  Lines — Railroad: 

Any  number  of  lessees  may  combine  their  interests  for  the  purpose  of 
constructing  and  operating  a refinery,  or  constructing  and  operating  a 
common  pipe  line,  or  railroad,  to  be  operated  and  used  by  them  jointly 
in  the  transportation  of  oil  from  their  wells,  or  from  the  wells  of  other 
lessees,  or  in  the  transportation  of  coal,  provided  application  is  made  to 
the  Secretary  of  the  Interior,  and  permission  is  granted  to  combine  such 
interests. 

Unlawful  Combined  Interests: 

Any  land  or  deposits  leased  by  any  lessee  which  may  be  controlled  by 
any  unlawful  trusts  or  combinations  by  the  consent  of  the  lessee,  or 
any  agreement  made  to  control  prices  or  output,  or  control  an  excessive 
area  as  provided,  shall  be  forfeited  by  regular  court  proceedings. 

Cancellation  of  Prospecting  Permits: 

Permits  to  prospect  any  government  land  may  be  cancelled  by  the 
Secretary  of  the  Interior  if  the  prospecting  work  is  not  carried  on  in  a 
diligent  manner,  and  according  to  the  terms  and  conditions  stated  in  the 
permit. 

Application  for  Permits  or  Leases: 

Application  for  permits,  addressed  to  the  Commissioner  of  the  General 
Office,  should  be  filed  in  the  local  land  office  for  the  district  in  which 
the  lands  or  deposits  desired  for  prospecting  or  leasing,  are  situated. 

Permits  and  Leases  on  Land  Patented  With  Mineral  Rights  Reserved: 

When  the  surface  rights  have  been  disposed  of  by  the  government  and 
the  mineral  rights  reserved,  a preference  right  for  a prospecting  permit  or 
a lease  in  case  of  discovery,  will  be  granted  to  the  holder  of  such  surface 
rights  as  stated  under  the  various  headings  for  each  particular  deposit. 

A prospecting  permit  or  lease  which  shall  apply  to  all  deposits  of  coal, 
phosphate,  oil,  oil  shale,  gas,  or  sodium,  may  be  granted  to  any  qualified 
person,  association,  subject  to  such  conditions  as  are  or  may  later  be 
provided. 


LEASING  OF  GOVERNMENT  LANDS 


41 


Right  of  Way  for  Pipe  Lines: 

Any  qualified  applicant  will  be  granted  a right  of*  way  through  the 
public  lands  or  forest  reserves  for  a pipe  line  for  the  transportation  of 
oil  or  natural  gas,  provided  that  the  pipe  line  shall  be  constructed, 
operated  and  maintained  as  a common  carrier.  The  right  of  way  shall 
be  for  the  tract  of  ground  occupied  by  the  pipe  and  25  feet  on  each  side, 
under  such  regulations  as  to  the  survey,  location,  application,  and  the 
use,  as  may  be  prescribed  by  the  Secretary  of  the  Interior. 

Every  lease  of  oil  land  shall  provide  that  the  lessee,  assignee,  or 
beneficiary,  if  owner,  or  operator,  or  owner  of  a controlling  interest  in 
a pipe  line,  or  of  any  company  operating  the  same,  shall  at  reasonable 
rates  and  without  discrimination  convey  the  oil  of  the  Government,  or 
of  any  citizen  or  company  not  the  owner  of  a pipe  line,  operating  a 
lease  or  purchasing  oil  or  gas  as  provided  in  the  Leasing  Act.  If  the 
above  provisions  are  not  complied  with,  a grant  for  a pipe  line  right  of 
way  will  be  forfeited. 

Right  of  Way  Over  Lands  Held  Under  Permit  or  Lease: 

The  Secretary  of  the  Interior  reserves  the  right  to  permit  upon  just 
terms,  such  easements,  or  rights  of  way,  over  any  land,  or  through  any 
tunnels,  on  any  lands  leased,  occupied,  or  even  subject  to  lease  or  occupa- 
tion, as  may  be  necessary  to  prospect  or  work  any  deposits  described  in 
the  Leasing  Act  and  likewise  for  the  shipment  and  treatment  of  material 
produced. 

Reserving  of  Surface  Rights  of  Lands  Leased: 

The  Secretary  of  the  Interior  may  reserve  as  much  of  the  surface 
rights  in  any  one  lease  as  will  not  be  necessary  for  the  use  of  the  lessee 
in  prospecting  or  working  the  deposit,  and  may  lease,  sell,  or  otherwise 
dispose  of  the  same.  When  any  surface  rights  are  reserved  by  the 
Secretary  of  the  Interior,  such  reservations  must  be  stated  in  the  lease. 

Assigning,  Sub-Leasing : 

No  lease  shall  be  assigned  or  sub-let  except  with  the  consent  of  the 
Secretary  of  the  Interior. 

Relinquishment  of  Lease: 

The  lessee  may,  in  the  judgment  of  the  Secretary  of  the  Interior,  be 
permitted  to  make  a written  relinquishment  of  all  rights  to  a lease  and 
if  accepted  shall  be  released  of  all  further  obligations.  A lessee  may 
also  surrender  any  portion  of  the  area  in  a lease  which  may  be  described 
by  legal  subdivisions. 

Methods  for  Working  Deposits: 

Each  lease  shall  contain  the  following  provisions,  provided  that  the 
provisions  do  not  conflict  with  the  laws  of  the  state  in  which  the  leased 
land  is  situated : 

1.  Skill  and  care  in  the  operation  of  the  property. 

2.  Safety  and  welfare  of  miners. 

3.  Prevention  of  undue  waste. 


42  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

4.  Working  day  of  8 hours  for  underground  miners  except  in  case 

of  emergency. 

5.  Non-employment  of  any  boy  under  sixteen  years  of  age,  or  of  any 

female  without  regard  to  age,  in  any  mining  operations  below 
the  surface. 

6.  Regulations  to  insure  the  fair  and  just  weighing  or  measurement 

of  coal  mined  by  each  miner. 

7.  Complete  freedom  of  purchase  for  all  workmen. 

8.  Payment  of  wages  at  least  twice  a month. 

9.  Sale  of  production  to  the  United  States  and  to  the  public  at 

reasonable  prices. 

10.  Protection  of  the  interests  of  the  United  States. 

11.  Prevention  of  monopoly. 

12.  Safe-guarding  of  the  public  welfare. 

COAL  LANDS. 

Permit  and  Lease: 

A permit  may  be  obtained  from  the  Secretary  of  the  Interior  by  any 
qualified  applicant  including  municipalities,  to  prospect  on  government 
land  for  coal,  or  to  explore  such  deposits,  or  to  determine  if  the  coal 
can  be  mined  at  a profit. 

Such  permits  will  be  granted  for  a period  of  two  years  for  a tract  of 
land  not  exceeding  2,560  acres  (4  sections). 

Discovery  of  Coal  by  the  Permiitee — Lease: 

If  coal  is  discovered  by  any  qualified  permittee  within  the  two-year 
period,  and  can  be  mined  in  commercial  quantities,  a lease  will  be  granted 
without  competitive  bidding  by  the  Secretary  of  the  Interior  for  all  or 
any  part  of  the  land  included  in  the  permit.  The  application  for  a lease 
should  be  filed  in  the  proper  district  land  office  before  th§  expiration 
of  the  period  of  the  permit. 

Railroads : 

A company  or  corporation  operating  a common  carrier  railroad  may 
hold  a permit  or  lease  for  coal  deposits,  provided  the  coal  is  for  its  own 
use  for  railroad  purposes.  Such  company  or  corporation  may  not  hold 
more  than  one  permit  or  lease  for  each  200  miles  of  its  road,  operated 
by  steam  within  the  state  in  which  the  coal  deposits  are  located.  Spurs, 
switches,  and  branch  lines  built  to  connect  the  leased  area  with  the  rail- 
road, shall  not  be  included  in  the  above  mileage. 

Areas  Leased: 

Coal  lands  will  be  divided  into  40-acre  tracts  or  multiples  thereof  by 
the  Secretary  of  the  Interior  upon  the  petition  of  any  qualified  applicant 
for  a lease,  but  no  tract  will  be  leased  which  contains  more  than  2,560 
acres  (4  sections). 

Method  of  Leasing: 

Leases  may  be  obtained  by  competitive  bidding  or  by  any  other  method 
adopted  by  the  Secretary  of  the  Interior,  provided  that  a notice  of  such 


LEASING  OF  COAL  LANDS 


43 


lease  has  been  given  for  30  days  in  a newspaper  in  the  county  in  which 
the  land,  or  coal  deposits  are  situated. 

Application  for  Leases  for  Land  Occupied  and  Improved: 

The  Secretary  of  the  Interior  is  authorized  in  awarding  leases  to  con- 
sider, and  recognize  equitable  rights  of  persons  who,  prior  to  February 
25,  1920,  have  improved,  occupied,  or  claimed  the  lands  offered  for 
leasing. 

Leasing  Additional  Land. 

When  a deposit  held  under  any  valid  lease  shall  be  worked  out  in  three 
years,  the  Secretary  of  the  Interior  may  lease  to  the  lessee  an  additional 
tract  of  land  or  coal  deposits,  upon  the  same  conditions  as  the  original 
lease,  but  the  combined  area  of  the  unworked  deposits  in  the  original 
lease,  and  the  area  of  the  additional  lease  must  not  exceed  2,560  acres. 

Consolidation  of  Leases: 

A number  of  lessees  may  surrender  their  original  leases,  and  then  con- 
solidate their  leases  by  including  in  a new  lease  such  areas,  not  to  exceed 
2,560  acres  of  adjoining  land,  provided  the  same  is  approved  by  the 
Secretary  of  the  Interior. 

Non-contiguouis  Land: 

The  Secretary  of  the  Interior  may  allow  a single  lease  for  non-con- 
tiguous  coal  land  not  exceeding  2,560  acres,  which  may  be  operated  as  a 
single  lease. 

Royalties  and  Rentals: 

The  amount  of  royalty  will  be  specified  in  the  lease  but  it  will  not  be 
less  than  five  cents  per  ton  of  2,000  pounds  mined.  An  annual  rental 
must  also  be  paid  in  advance.  Such  rental  will  be  specified  in  the  lease, 
and  will  not  be  less  than  twenty-five  cents  per  acre  for  the  first  year, 
fifty  cents  an  acre  for  the  second,  third,  fourth,  and  fifth  years,  and  not 
less  than  one  dollar  per  acre  for  each  year  thereafter  during  the  period 
of  the  lease. 

All  rentals  for  any  year  will  be  credited  against  the  royalties  as  they 
accumulate  for  that  year. 

Period  of  Lease: 

A lease  may  be  granted  for  intermediate  periods  provided  the  deposits 
are  worked  continuously  and  in  a diligent  manner,  except  when  in- 
terrupted by  strikes  or  other  causes  not  attributal  to  the  lessee.  At  the 
end  of  twenty  years  the  Secretary  of  the  Interior  may  make  any  changes 
in  the  terms  and  conditions  of  the  lease  as  he  determines,  unless  provided 
otherwise  by  law.  The  Secretary  of  the  Interior  may  permit  the  sus- 
pension of  operations  under  such  lease  for  a period  not  to  exceed  six 
months  at  any  one  time  when  market  conditions  are  such  that  the  mine 
cannot  operate  except  at  a loss. 

License  to  Cities  and  Individuals  for  Domestic  Purposes: 

Cities  may  obtain  a limited  license  or  permit  from  the  Secretary  of 
the  Interior  for  the  purpose  of  mining  coal  and  disposing  of  the  same 


44  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

to  the  residents  of  the  city  for  household  use.  The  land  is  to  be  selected 
within  the  same  state  in  which  the  city  is  located.  The  amount  of 
land  allowed  in  a permit  is  as  follows:  Not  more  than  320  acres  for  a 
city  having  less  than  100.000  population,  and  not  more  than  1,280  acres 
for  a city  having  100,000  to  150,000  population,  and  not  more  than  2,560 
acres  for  a city  having  a population  greater  than  150,000.  When  such 
a limited  license  or  permit  is  granted,  no  royalty  or  rental  is  charged 
provided  the  coal  is  sold  to  the  residents  without  profit.  When  a limited 
license  or  permit  is  held  by  a city,  it  will  in  no  wTay  interfere  with  a 
regular  lease  held  by  the  city  for  coal  land  as  provided  in  the  Leasing 
Act. 

Individuals  or  associations  of  individuals  may  obtain  a limited  license 
or  permit  to  prospect,  mine,  and  take  coal  from  public  lands  for  their 
own  use  without  the  payment  of  royalty  or  rental.  Under  no  conditions 
may  coal  mined  under  such  a limited  license  be  sold. 

A corporation  may  not  obtain  a limited  license  or  permit. 

PHOSPHATE  LANDS. 

Government  land  containing  deposits  of  phosphate  may  be  leased 
by  the  Secretary  of  the  Interior  to  any  qualified  person  through  adver- 
tisement, competitive  bidding,  or  any  other  method  that  he  may  adopt. 

Size  of  Lease — Shape: 

No  lease  may  be  obtained  for  more  than  2,560  acres  (4  sections) 
which  must  be  described  by  legal  subdivision  when  on  surveyed  land. 
All  leased  land  must  be  in  compact  form  and  its  length  must  not  be  more 
than  two  and  one-half  times  its  width. 

Lease  on  Unsurveyed  Land: 

If  a lease  is  applied  for  on  unsurveyed  land,  the  land  will  be  surveyed 
by  the  Government  at  the  expense  of  the  applicant,  in  accordance  with 
the  rules  and  regulations  prescribed  by  the  Secretary  of  the  Interior,  and 
the  lands  leased  must  conform  to  legal  subdivisions. 

Royalties  and  Rentals: 

All  royalties  shall  be  specified  in  the  lease  by  the  Secretary  of  the 
Interior,  but  in  no  case  shall  they  be  less  than  two  per  cent  of  the  gross 
value  of  the  output  of  phosphates  or  phosphate  rock  at  the  mine. 

An  annual  rental,  payable  in  advance,  shall  be  fixed  by  the  Secretary 
of  the  Interior  but  in  no  case  shall  it  be  less  than  25  cents  per  acre  for 
the  first  year,  50  cents  per  acre  for  the  second,  third,  fourth  and  fifth 
years,  and  $1.00  per  acre  for  each  and  every  year  thereafter  during  the 
life  of  the  lease.  Such  rentals  shall  be  credited  against  the  royalties  for 
that  year. 

Period  of  Lease: 

Leases  shall  be  for  an  intermediate  period  upon  condition  of  a minimum 
annual  production,  except  where  strikes,  not  attributable  to  the  lessee, 
interfere  with  the  operation. 


OIL  AND  GAS  LANDS 


45 


At  the  end  of  each  20-year  period  the  Secretary  of  the  Interior  may 
make  any  readjustments  of  terms  and  conditions  as  he  finds  necessary, 
unless  otherwise  provided  by  law  at  the  end  of  such  periods. 

Suspension  of  Operations: 

The  Secretary  of  the  Interior  may  permit  the  suspension  of  operations 
for  a period  not  exceeding  twelve  months  at  any  one  time  when  market 
conditions  are  such  that  work  cannot  be  continued  except  at  a loss  to 
the  lessee. 

Additional  Lands: 

Any  lessee  may  obtain  a permit  for  additional  surface  rights  not  to 
exceed  40  acres  of  unappropriated  land  for  the  purpose  of  prospecting, 
development,  extraction,  treatment,  and  removal  of  such  phosphate  de- 
posits. 

OIL  AND  GAS  LANDS. 

Permit  for  Unappropriated  Lands: 

A permit  to  prospect  for  oil  and  gas  may  be  obtained  from  the  Secretary 
of  the  Interior  by  any  qualified  applicant  for  a period  not  exceeding  two 
years  upon  a tract  of  unappropriated  government  land  not  exceeding 
2,560  acres. 

No  Permits  for  Land  in  Known  Oil  or  Gas  Field: 

No  permit  will  be  granted  for  land  within  any  known  geological  struc- 
ture of  a producing  oil  or  gas  field. 

Location  of  Lands: 

Any  land  for  which  a permit  shall  be  applied  for  must  be  located  in  a 
compact  form  according  to  legal  subdivisions,  if  surveyed,  and  in  ap- 
proximately square  or  rectangular  form  if  on  unsurveyed  land,  the  length 
of  which  must  not  be  more  than  two  and  one-half  times  its  width.  In 
contiguous  tracts  may  be  located  under  certain  conditions  due  to  prior 
locations.  All  locations  must  be  made  before  filing  an  application  for  a 
permit. 

Preference  Right  to  a Permit: 

Any  applicant  shall  be  entitled  to  a preference  right  to  a permit  for  a 
period  of  thirty  days,  after  erecting  a monument  not  less  than  four  feet 
high  and  not  less  than  four  inches  square  or  in  diameter,  at  some  con- 
spicuous place  on  the  land  located,  and  after  posting  a proper  notice  in 
writing  on  or  near  such  monument.  Such  notice  must  contain  the  date, 
and  hour  of  posting,  name  of  applicant,  a description  of  the  land  to  be 
covered  by  the  permit  by  reference  to  courses  and  distances  from  the 
monument  and  from  any  other  natural  object  and  permanent  monuments 
as  will  identify  the  land,  stating  the  area  in  acres  thereof,  and  also  stating 
that  an  application  for  a permit  will  be  made  within  thirty  days  after 
posting  such  notice. 

Terms  and  Conditions  of  Permit: 

Within  90  days  after  receiving  permit,  the  corners  of  the  land  included 
in  the  permit  must  be  marked  with  substantial  monuments  and  a notice, 


46  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

stating  that  a permit  has  been  granted  and  giving  also,  a description  of 
the  land  included  in  the  permit,  must  be  posted  at  some  conspicuous  place. 

Work  Required: 

Drilling  operations  must  begin  within  six  months  from  the  date  of 
permit. 

Within  one  year,  one  or  more  wells,  not  less  than  six  inches  in  diameter, 
must  be  drilled  to  a depth  of  not  less  than  500  feet  eaqji,  unless  valuable 
deposits  of  oil  are  discovered  at  less  depth. 

Within  twro  years  one  or  more  wells  to  a depth  of  not  less  than  2,000 
feet  must  be  drilled  unless  valuable  deposits  are  sooner  discovered. 

A permit  may  be  extended  for  a period  of  two  years  by  the  Secretary 
of  the  Interior  when  the  permittee  has  not  been  able  to  prospect  the 
ground  properly. 

Location  of  Wells: 

No  wells  may  be  drilled  for  oil  or  gas  within  200  feet  of  the  outer 
boundaries  of  the  land  covered  by  a permit  or  lease,  unless  the  adjoining 
lands  have  been  patented  or  title  otherwise  held  by  private  owners. 

Precautions  when  Drilling: 

A permit  shall  be  granted  only  upon  the  conditions  that  all  necessary 
precautions  will  be  taken  to  prevent  the  waste  of  any  oil  or  gas  developed 
in  the  land,  and  to  prevent  any  water  from  entering  the  wells  drilled, 
which  may  in  any  way  cause  or  injure  the  oil  or  gas  deposits.  A permit 
shall  be  forfeited  if  the  above  precautions  are  not  observed  while  drilling. 

Extension  of  Life  of  Permit: 

If  the  permittee  is  unable,  with  the  exercise  of  diligence,  to  test  the 
land  within  two  years,  an  application  for  an  extension  of  time,  not  to 
exceed  two  years  may  be  filed  during  the  period  of  the  permit.  Reasons 
must  be  given  for  applying  for  such  extension  of  time. 

Discovery  of  Oil  or  Gas: 

When  oil  or  gas  is  discovered  on  lands  covered  by  a valid  permit,  the 
permittee  shall  be  entitled  to  lease  one-fourth  of  the  land  held  under  the 
permit,  or  in  any  case,  the  permittee  shall  be  entitled  to  lease  160  acres  if 
there  are  that  many  acres  within  the  permit. 

The  permittee  shall  also  be  entitled  to  a preference  right  to  lease  the 
remainder  of  the  land  covered  by  his  prospective  permit,  but  the  same 
may  be  obtained  only  by  competitive  bidding,  or  by  any  other  method 
prescribed  by  the  Secretary  of  the  Interior. 

Royalty  Before  Applying  for  Lease: 

The  royalty  on  all  oil  or  gas  produced  upon  lands  held  by  a permit  will 
be  twenty  per  cent  of  the  gross  value  until  such  time  as  the  permittee 
makes  application  for  a lease  for  the  one-quarter  of  the  permit  area. 

Description  of  Land  Selected  for  Lease: 

All  lands  selected  for  leasing  must  be  in  compact  form  and  described 
by  legal  subdivision  of  the  public  land  surveys. 


OIL  AND  GAS  LANDS 


47 


When  tracts  are  selected  on  unsurveyed  land  they  shall  be  surveyed  by 
the  government  in  proper  manner  and  at  the  expense  of  the  applicant  for 
a lease. 

Life  of  Lease: 

Leases  shall  be  for  periods  of  twenty  years  and  the  lessee  may  also 
have  a preference  right  to  renew  his  lease  for  periods  of  ten  years  upon 
terms  prescribed  by  the  Secretary  of  the  Interior. 

Royalties  and  Rental  upon  Leased  Land: 

The  royalty  charged  upon  leased  lands  included  in  the  one-fourth  of  the 
original  permit  will  be  five  per  cent  in  amount  of  oil  or  gas,  or  in  actual 
value  of  the  production. 

The  royalties  in  all  other  leases  for  oil  or  gas  shall  be  determined  by 
competitive  bidding,  or  by  other  methods  as  perscribed  by  the  Secretary 
of  the  Interior,  but  shall  not  be  less  than  twelve  and  one-half  per  cent  in 
amount  or  value  of  production. 

The  annual  rental  for  all  leases  for  oil  or  gas  lands  shall  be  one  dollar 
per  acre,  payable  in  advance,  and  the  rental  paid  will  be  credited  against 
the  royalties  as  they  accumulate  for  that  year. 

Reduction  of  Royalty: 

Whenever  the  average  daily  production  of  any  oil  well  does  not  exceed 
ten  barrels  the  Secretary  of  the  Interior  is  authorized  to  reduce  the  royalty 
on  future  production,  provided  that  the  wells  cannot  be  successfully 
operated  upon  the  royalties  fixed  in  the  lease  The  royalty  upon  any  gas 
lease  will  likewise  be  reduced  when  the  production  decreases  so  that  the 
well  cannot  be  operated  except  at  a loss. 

Leasing  of  Land  in  a Producing  Oil  or  Gas  Field: 

All  land  or  deposits  within  the  known  geological  structure  of  a pro- 
ducing oil  or  gas  field  may  be  leased  to  the  highest  qualified  bidder  for 
an  area  not  exceeding  six  hundred  and  forty  acres.  Such  area  shall  not 
exceed  in  length  two  and  one-half  times  its  width. 

The  royalty  on  such  deposits  will  not  be  less  than  twelve  and  one-half 
per  cent  in  amount  or  value  of  production,  and  the  annual  rental  not  less 
than  one  dollar  per  acre. 

Preference  Right  of  Owner  of  Surface: 

A preference  right  to  a permit  and  to  a lease  in  case  of  discovery,  will 
be  granted  to  any  one  who  has  entered,  or  patented  an  agricultural  tract 
with  the  mineral  rights  reserved,  provided  the  land  was  not  withdrawn  or 
classified  as  oil  or  gas  land  at  the  time  of  entry.  A like  permit  and  lease 
will  be  granted  to  an  assignee  where  the  assignment  was  made  prior  to 
January  1,  1918.  Such  a permit  or  lease  will  not  be  granted  on  lands  in- 
cluded in  any  railroad  grant. 

A joint  application  for  a permit  not  to  exceed  2,560  acres  may  be  made 
by  the  holders  of  such  lands  within  an  area  not  greater  than  a township 
(36  sections).  The  royalty  and  conditions  of  a lease,  in  case  of  discovery 
will  be  the  same  as  stated  before. 


48  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

Application  by  Other  Persons: 

An  application  for  a permit  for  entered  or  patented  lands,  where  the 
oil  and  gas  has  been  reserved  may  be  filed  by  a person  other  than  the 
entryman  or  owner  of  the  land,  provided  that  the  applicant  serve  personal 
notice  of  such  application  upon  the  owner  or  owners  of  the  land.  Upon 
receiving  such  notice,  the  owner  of  the  land  must  file  an  application  within 
thirty  days  in  the  proper  local  land  office,  if  he  desires  to  exercise  his 
preference  right,  if  any.  to  a permit  for  such  land.  The  preference  right 
applicant  must  furnish  evidence  that  personal  notice  was  served  on  the 
owner,  and  that  the  party  served  is  the  owner  of  the  land  involved. 

Government  to  Extract  Helium  from  Gas: 

The  Government  reserves  the  right  to  extract  helium  from  all  gas  pro- 
duced from  land  permitted,  leased,  or  otherwise  granted  under  the  pro- 
visions of  the  Leasing  Act. 

OIL  SHALE  LANDS 

The  Secretary  of  the  Interior  is  authorized  to  lease  any  deposits  of  oil 
shale  belonging  to  the  United  States  to  any  qualified  person  or  corpora- 
tion, and  under  such  rules  and  regulations  as  he  may  prescribe. 

Size  of  Lease: 

No  lease  shall  be  granted  for  an  area  exceeding  5,120  acres  (8  sections) 
which  must  be  described  by  legal  subdivision.  When  the  land  is  unsur- 
veyed it  will  be  surveyed  by  the  government,  but  at  the  expense  of  the 
applicant  for  lease. 

Period  of  Lease: 

A lease  will  be  granted  for  indeterminate  periods  upon  such  conditions 
as  the  Secretary  of  the  Interior  may  include,  relative  to  the  methods  of 
mining,  development,  and  prevention  of  waste. 

Royalties  and  Rental: 

The  royalty  charged  for  an  oil  shale  lease  will  be  specified  in  the  lease, 
and  the  annual  rental,  payable  at  the  beginning  of  each  year,  will  be  fifty 
cents  per  acre.  The  rental  paid  will  be  credited  against  the  royalties.  The 
royalties  may  be  readjusted  at  the  end  of  each  twenty  year  period. 

In  order  to  encourage  production  of  petroleum  products,  the  payment  of 
the  annual  rental  and  royalty  may  be  waived  by  the  Secretary  of  the 
Interior  for  the  first  five  years  of  such  lease. 

Claims  Held  Under  Former  Laws: 

Any  person  having  a valid  claim  under  existing  laws  of  January  1,  1919, 
and  who  relinquishes  the  same  to  the  United  States,  will  be  entitled  to  a 
lease  for  such  area  of  the  land  relinquished  as  shall  not  exceed  5,120  acres 
(8  sections). 

Anyone  who  has  been  found  guilty  of  fraud,  or  who  has  knowledge  of 
fraud,  or  who  has  been  dishonest  shall  not  be  entitled  to  such  a lease. 
Only  one  lease  shall  be  granted  to  any  person,  association  or  corporation. 


SODIUM  LANDS 


49 


SODIUM  LANDS 

Permit : 

A permit  to  prospect  for  deposits  containing  sodium  as  chlorides,  sul- 
phates, carbonates,  borates,  silicates,  or  nitrates,  for  a period  of  two  years, 
shall  be  granted  to  any  applicant  for  an  area  not  to  exceed  2,560  acres,  in 
a reasonably  compact  form,  by  legal  subdivision  if  surveyed ; if  unsurveyed 
by  metes  and  bounds  description. 

Lease: 

If  a valuable  discovery  of  such  deposits  is  made  within  two  years,  the 
permittee  shall  be  entitled  to  a lease  for  one-half  of  the  land  included  in 
the  permit,  but  not  to  exceed  1,200  acres  according  to  legal  subdivisions.  If 
the  land  containing  such  deposits  is  unsurveyed,  it  will  be  surveyed  by 
the  government  at  the  expense  of  the  permittee.  The  permittee  has  also  a 
preference  right  to  lease  the  remaining  one-half  of  the  land  included  in  his 
permit. 

Royalty : 

The  lands  shall  be  leased  at  a royalty  of  not  less  than  twelve  and  one- 
half  per  cent  of  the  amount  or  value  of  the  production. 

Known  Deposits  of  Sodium: 

Lands  known  to  contain  deposits  of  sodium  and  not  held  by  permits  or 
leases,  may  be  leased  through  the  Secretary  of  the  Interior  by  advertise- 
ment, competitive  bidding,  or  as  he  may  adopt,  and  in  any  area  not  to 
exceed  2,560  acres. 

Rental : 

The  annual  rental  shall  be  paid  in  advance  at  a rate  of  fifty  cents  per 
acre  for  the  first  calendar  year  or  fraction  thereof,  and  one  dollar  per 
acre  per  annum  thereafter.  Rentals  shall  be  credited  against  the  royalties 
for  each  year. 

Period  of  Lease: 

Leases  shall  be  for  indeterminate  periods  subject  to  readjustment  at  the 
end  of  each  twenty  year  period. 

Additional  Lands: 

An  additional  forty-acre  tract  of  unoccupied,  non-mineral  land  may  be 
rented  to  a permittee  or  a lessee  of  sodium  deposits  at  the  rate  of  twenty- 
five  cents  per  acre,  for  camp  sites,  refining  works,  and  other  purposes 
connected  with  and  necessary  to  the  proper  development  and  the  use  of 
the  deposits  covered  by  the  permit  or  lease. 


MINING  LAWS  OF  MONTANA 


REVISED  CODES  OF  1921. 


Location  and  Record  of  Mining  and  Millsite  Claims. 


Section  7365. 

7366. 
“ 7367. 

“ 7368. 

“ 7369. 

“ 7370. 

“ 7371. 

“ 7372. 

“ 7373. 

“ 7374. 

“ 7375. 

“ 7376. 

“ 7377. 

“ 7378. 

“ 7379. 

“ 7380. 

“ 7381. 

“ 7382. 

“ 7383. 

“ 7384. 


Discovery-Notice  Marking  Boundaries-Sinking 
Shaft. 

Record  of  Certifiacte  of  Location. 

Placer  Locations  Heretofore  Made,  Effect  of. 
Annual  Work-Affidavit-Contents-Record. 
Millsites. 

Relocation  of  Abandoned  Claim. 

Rights  of  Relocator. 

Amended  Location. 

Relocation  by  Owner. 

Amendment  or  Relocation  Not  a Waiver  of 
Acquired  Rights.  . 

Rights  of  Third  Persons  Not  Affected. 
Validating  Locations  Heretofore  Made. 
Defective  Locations  Good  Against  Persons 
With  Notice. 

Effect  of  Patent. 

Amended  Locations. 

Effect  of  Amended  or  Additional  Declaratory 
Statement. 

Location  of  Mining  Claims  on  State  Land. 
Owners  of  Mines  Have  Right-of-way. 
Right-of-way  for  Road  or  Ditch. 

Proceedings  to  Obtain  Right-of-way. 


Section  7365.  Discovery — Notice — Marking — Boundaries — Sinking  Shaft. 

Any  person  who  discovers,  upon  the  public  domain  of  the  United  States, 
within  the  State  of  Montana,  a vein,  lode  or  ledge  of  rock  in  place,  bear- 
ing gold,  silver,  cinnabar,  lead,  tin,  copper  or  other  valuable  deposits,  or 
a placer  deposit  of  gold,  or  other  deposit  of  minerals  having  a commercial 
value  which  is  subject  to  entry  and  patent  under  the  mining  laws  of  the 
United  States,  may,  if  qualified  by  the  laws  of  the  United  States,  locate  a 
mining  claim  upon  such  vein,  lode,  ledge  or  deposit,  in  the  following 
manner,  viz. : 

I.  He  shall  post,  conspicuously,  at  the  point  of  discovery  a written  or 
printed  notice  of  location,  containing  the  name  of  the  claim,  the  name  of 
the  locator  (or  locators,  if  there  be  more  than  one),  the  date  of  the  loca- 
tion, which  shall  be  the  date  of  posting  such  notice,  and  the  approximate 
dimensions  of  area  of  the  claim  intended  to  be  appropriated. 

II.  Within  thirty  days  after  posting  the  notice  of  location,  he  shall 
distinctly  mark  the  location  on  the  ground  so  that  its  boundaries  can  be 
readily  traced.  It  shall  be  prima  facie  evidence  that  the  location  is 
properly  marked  if  the  boundaries  are  defined  by  a monument  at  each 
corner  or  angle  of  the  claim,  consisting  of  any  one  of  the  following  kinds : 


— 50  — 


MINING  LAWS  OF  MONTANA.  REVISED  CODE  1921 


51 


(1)  A tree  at  least  eight  inches  in  diameter,  and  blazed  on  four  sides.  (2) 
A post  at  least  four  inches  square  by  four  feet  six  inches  in  length,  set  one 
foot  in  the  ground,  unless  solid  rock  should  occur  at  a less  depth,  in  which 
case  the  post  should  be  set  upon  such  rock,  and  surrounded  in  all  cases  by 
a mound  of  earth  or  stone  at  least  four  feet  in  diameter  by  two  feet  in 
height.  A squared  stump,  of  the  requisite  size,  surrounded  by  such  mound, 
shall  be  deemed  the  equivalent  of  a post  and  mound.  (3)  A stone  at  least 
six  inches  square  by  eighteen  inches  in  length,  set  two-thirds  of  its  length 
in  the  ground,  with  a mound  of  earth  or  stone  alongside  at  least  four  feet 
in  diameter  by  two  feet  in  height,  or  (4)  a boulder  at  least  there  feet 
above  the  natural  surface  of  the  ground  on  the  upper  side. 

Where  other  monuments,  or  monuments  of  lesser  dimensions  than  those 
above  described,  are  used,  it  shall  be  a question  for  the  jury,  or  for  the 
court  where  the  action  is  tried  without  a jury,  as  to  whether  the  location 
has  been  marked  upon  the  ground  so  that  its  boundaries  can  be  readily 
traced.  Whatever  monument  is  used,  it  must  be  marked  with  the  name 
of  the  claim  and  the  designation  of  the  corner,  either  by  number  or  car- 
dinal point. 

III.  Within  sixty  days  after  posting  such  notice,  he  shall  sink  a shaft 
upon  the  vein,  lode  or  deposit,  at  or  near  the  point  of  discovery,  to  be 
known  as  the  discovery  shaft.  Such  shaft  shall  be  sunk  to  the  depth  of  at 
least  ten  feet,  vertically,  below  the  lowest  part  of  the  rim  of  such  shaft 
at  the  surface,  or  deeper  if  necessary  to  disclose  the  vein  or  deposit  located, 
and  the  cubical  contents  of  such  shaft  shall  be  not  less  than  one  hundred 
and  fifty  cubic  feet ; provided,  that  any  cut  or  tunnel  which  discloses  the 
vein,  lode  or  deposit  located  at  a vertical  depth  of  at  least  ten  feet  below 
the  natural  surface  of  the  ground  and  which  constitutes  at  least  one  hun- 
dred and  fifty  cubic  feet  of  excavation,  shall  be  deemed  the  equivalent  of 
such  shaft,  and,  provided  also,  that,  where  the  vein,  lode  or  deposit 
located  is  disclosed  at  a less  vertical  depth  than  ten  feet,  any  deficiency  in 
the  depth  of  the  discovery  shaft,  cut  or  tunnel  may  be  compensated  for  by 
any  horizontal  extension  of  such  working,  or  by  any  excavation  done  else- 
where upon  the  claim,  equaling,  in  cubical  contents,  the  cubical  extent  of 
such  deficiency ; but  in  every  case  at  least  seventy-five  cubic  feet  of  exca- 
vation shall  be  made  at  the  point  of  discovery. 

Section  7366.  Record  of  Certificate  of  Location. — Within  sixty  days 
after  posting  the  notice  of  location  and  for  the  purpose  of  constituting 
constructive  notice  of  the  location,  the  locator  shall  record  his  location  in 
the  office  of  the  County  Clerk  of  the  county  in  which  such  mining  claim 
is  situated.  Such  record  shall  consist  of  a certificate  of  location  con- 
taining : 

1.  The  name  of  the  lode  or  claim. 

2.  The  name  of  the  locator  or  locators,  if  there  be  more  than  one. 

3.  The  date  of  location,  and  such  description  of  said  claim,  with 
reference  to  some  natural  object  or  permanent  monuments,  as  will  identify 
the  claim. 

IV.  In  the  case  of  a lode  claim,  the  direction  and  distance  claimed 
along  the  course  of  the  vein  each  way  from  the  discovery  shaft,  cut  or 
tunnel,  with  the  width  claimed  on  each  side  of  the  center  of  the  vein. 


52  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

V.  In  the  case  of  a placer  claim,  the  dimensions  or  area  of  the  claim, 
and  the  location  thereon  of  the  discovery  shaft,  cut  or  tunnel. 

VI.  The  locator  and  claimant,  at  his  option,  may  also  set  forth,  in  such 
certificate  of  location,  a description  of  the  discovery  work,  the  corner 
monuments  and  the  markings  thereon,  and  any  other  facts  showing  a 
compliance  with  the  provisions  of  this  law. 

Such  certificate  of  location  must  be  verified,  before  some  officer  au- 
thorized to  administer  oaths,  by  the  locator,  or  one  of  the  locators,  if  there 
be  more  than  one,  or  by  authorized  agent.  In  the  case  of  a corporation,  the 
verification  may  be  made  by  any  officer  thereof,  or  by  an  authorized 
agent.  When  the  verification  is  made  by  an  agent,  the  fact  of  the  agency 
shall  be  stated  in  the  affidavit. 

A certificate  of  location  so  verified,  or.  a certified  copy  thereof,  is  prima 
facie  evidence  of  all  facts  properly  recited  therein. 

Section  7367.  Placer  Locations  Heretofore  Made — Effect  of.  All  placer 
mining  locations  or  locations  of  valuable  mineral  deposits,  which  have 
heretofore  been  recorded  in  the  office  of  the  County  Clerk  or  Recorder, 
have  the  same  force  and  effect  as  though  such  records  had  been  authorized 
by  law,  except  in  cases  where  the  rights  of  third  persons  had  been  ac- 
quired before  the  passage  of  this  code;  and  such  record  is  entitled  to  be 
admitted  in  evidence  in  any  court. 

Section  7368.  Annual  Work — Affidavit — Contents — Record.  The  owner 
of  a lode  or  placer  claim  who  performs  or  causes  to  be  performed  the 
annual  work  or  makes  the  improvements  required  by  the  laws  of  the 
United  States,  in  order  to  prevent  the  forfeiture  of  the  claim,  may,  within 
twenty  days  after  the  annual  work,  file  in  the  office  of  the  county  clerk 
of  the  county  in  which  such  claim  is  situated  an  affidavit  of  his  own,  or 
an  affidavit  of  the  person  who  performed  such  work  or  made  the  improve- 
ments, showing : 

1.  The  name  of  the  mining  claim,  and  where  situated. 

2.  The  number  of  days  work  done,  and  the  character  and  value  of  the 
improvements  placed  thereon ; 

3.  The  date  of  performing  such  work,  and  of  making  the  improvements ; 

4.  At  whose  instance  the  work  was  done  or  the  improvements  made; 

5.  The  actual  amount  paid  for  work  and  improvements,  and  by  whom 
paid  when  the  same  was  not  done  by  the  owner. 

Such  affidavits,  or  a certified  copy  thereof,  are  prima  facie  evidence  of 
the  facts  therein  stated. 

Section  7369.  Mill  Sites.  Mill  site  claims  may  be  located  and  recorded 
in  the  same  manner  as  other  claims,  except  that  no  discovery  or  discovery 
work  is  required.  Where  a mill  site  claim  is  appurtenant  to  a mining 
claim,  the  certificate  of  location  of  such  mill  site  claim  shall  describe,  by 
appropriate  reference,  the  mining  claim  to  which  it  is  appurtenant. 

Section  7370.  Relocation  of  Abandoned  Claim.  The  relocator  of  an 
abandoned  or  forfeited  mining  claim  may  adopt  as  his  discovery  any  shaft 
or  other  working,  existing  upon  such  claim  at  the  date  of  the  relocation, 


MINING  LAWS  OF  MONTANA.  REVISED  CODE  1921 


53 


in  which  the  vein,  lode  or  deposit  is  disclosed,  but,  in  such  shaft  or  other 
working,  he  shall  perform  the  same  discovery  work  as  is  required  in  the 
case  of  an  original  location. 

Section  7371.  Rights  of  Relocator.  The  rights  of  a relocator  of  any 
abandoned  or  forfeited  mining  claim,  hereafter  relocated,  shall  date  from 
the  posting  of  his  notice  of  location  thereon,  and,  while  he  is  duly  perform- 
ing the  acts  required  by  law  to  perfect  his  location,  his  rights  shall  not 
be  affected  by  any  re-entry  or  resumption  of  work  by  the  former  locator 
or  claimant. 

Section  7372.  Amended  Location.  A locator  or  claimant  may  at  any 
time,  amend  his  location  and  make  any  change  in  the  boundaries  which 
does  not  involve  a change  in  the  point  of  discovery  as  shown  by  the  dis- 
covery shaft  by  marking  the  location  as  amended  upon  the  ground,  and 
filing  an  amended  certificate  of  location  conforming  to  the  requirements 
of  an  original  certificate  of  location.  A defect  in  a recorded  certificate 
of  location  may  be  cured  by  filing  an  amended  certificate. 

Section  7373.  Relocation  by  Owner.  A locator  or  claimant  may,  at  any 
time,  re-locate  his  own  claim  for  any  purpose,  except  to  avoid  the  per- 
formance of  annual  labor  thereof,  and,  by  such  re-location,  may  change 
the  boundaries  of  his  claim,  or  the  point  of  discovery,  or  both,  but  such  re- 
location must  comply,  in  all  respects,  with  the  requirements  of  this  law 
as  to  an  original  location. 

Section  7374.  Amendment  or  Relocation  Not  a Waiver  of  Acquired 
Rights.  Where  a locator  or  claimant  amends  or  relocates  his  own  claim, 
such  amendment  or  re-location  shall  not  be  construed  as  a waiver  of  any 
right  or  title  acquired  by  him  by  virtue  of  the  previous  location  or  record 
thereof,  except  as  to  such  portions  of  the  previous  location  as  may  be 
omitted  from  the  boundaries  of  the  claim  as  amended  or  re-located. 

As  to  the  portion  of  ground  included  both  in  the  original  location  and 
the  location  as  amended  or  relocated,  he  may  rely  either  upon  the  original 
location  or  the  location  as  amended  or  re-located,  or  upon  both.  Provided, 
that  nothing  herein  contained  shall  be  construed  as  permitting  the  locator 
or  claimant  to  hold  a tract  which  does  not  include  a valid  discovery. 

Section  7375.  Rights  of  Third  Persons  not  Affected.  No  amendment  or 
re-location  of  a mining  claim  by  the  locator  or  claimant  thereof  shall 
interfere  with  the  right  of  any  third  person  existing  at  the  time  of  such 
amendment  or  re-location. 

Section  7376.  Validating  Locations  Heretofore  Made.  All  mining  loca- 
tions, made  and  recorded  under  the  laws  of  this  State,  heretofore  in  force, 
that  in  any  respect  have  failed  to  conform  to  the  requirements  of  such 
laws,  shall,  nevertheless,  in  the  absence  of  the  rights  of  third  persons 
accruing  prior  to  the  passage  of  this  Act,  be  valid  if  the  making  and 
recording  of  such  locations  conform  to  the  requirements  of  this  Act. 

Section  7377.  Defective  Locations  Good  Against  Persons  With  Notice. 

The  period  of  time  prescribed  by  this  law  for  the  performance  of  any  act, 
shall  not  be  deemed  mandatory  where  the  act  is  performed  before  the 
rights  of  the  third  persons  have  intervened,  and  no  defect  in  the  posted 


54  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

notice  or  recorded  certificate  shall  be  deemed  material,  except  as  against 
one  who  has  located  the  same  ground,  or  some  portion  thereof,  in  good 
faith  and  without  notice.  Notice  to  an  agent,  who  makes  a location  in 
behalf  of  another,  shall  be  deemed  notice  to  his  principal  and  notice  to 
one  of  several  co-claimants  shall  be  deemed  notice  to  all. 

Section  7378.  Effect  of  Patent.  The  issuance  of  a United  States  patent 
for  a mining  claim  shall  be  deemed  conclusive  that  the  requirements  of 
the  laws  of  this  State  relative  to  the  location  and  record  of  such  mining 
claim  have  been  duly  complied  with ; provided,  however,  that  where  ques- 
tions of  priority  are  involved  the  date  of  the  location  shall  be  an  issuable 
fact  where  it  is  claimed  to  have  been  prior  to  the  date  of  the  record  of  the 
location. 

Section  7379.  Amended  Locations.  If  at  any  time  the  locator  of  any 
mining  claim  heretofore  or  hereafter  located,  or  his  successors  or  assigns 
shall  apprehend  that  his  original  declaratory  statement  was  defective  or 
erroneous,  or  that  the  requirements  of  law  had  not  been  complied  with,  or 
shall  be  desirous  of  changing  his  boundaries,  or  taking  any  part  of  an 
overlapping  claim  which  has  been  abandoned,  or  in  case  his  original  de- 
claratory statement  was  filed  prior  to  the  passage  of  this  law,  and  he  shall 
be  desirous  of  securing  the  benefit  of  this  Act,  such  locator,  or  his  suc- 
cessors or  assigns,  may  file  an  additional  or  amended  declaratory  state- 
ment, subject  to  the  provisions  of  this  Act ; provided  that  such  relation  or 
filing  of  an  amended  or  additional  declaratory  statement  shall  not  inter- 
fere with  the  existing  rights  of  others  at  the  time  of  such  relocation  or 
filing  of  the  amended  or  additional  declaratory  statement,  and  no  such 
relocation  or  amended  or  additional  declaratory  statement,  or  other  record 
thereof,  shall  preclude  the  claimant  or  claimants  from  proving  any  such 
title  as  he  or  they  may  have  held  under  the  previous  location  and  notice 
thereof. 

Section  7380.  Effect  of  Amended  or  Additional  Declaratory  Statement. 

Any  amended  or  additional  declaratory  statement  which  may  have  here- 
tofore been  filed  by  a locator,  or  his  successors  or  assigns,  shall  have  the 
same  force  and  effect  and  be  subject  to  the  same  terms  and  conditions  as 
though  the  same  had  been  filed  under  the  provisions  of  the  proceeding 
section. 

Section  7381.  Location  of  Mining  Claims  on  State  Lands.  The  location 
of  mining  claims  upon  state  land  is  provided  for  by  sections  1905  and 
1906  of  the  Political  Code.  (See  page  67.) 

Section  7382.  Owners  of  Mines  have  Right-of-way.  The  owner  of  a 
mining  claim  held  under  the  laws  of  the  United  States  by  patent  or 
otherwise,  or  under  the  local  laws  and  customs  of  the  state,  has  a right- 
of-way  over  and  across  the  land  or  mining  claim,  patented  or  otherwise, 
of  another,  as  prescribed  in  this  chapter. 

Section  7383.  Right-of-way  for  Road  or  Ditch.  Whenever  a mine  or 
inning  claim  is  so  situated  that  it  cannot  be  conveniently  worked  without 
a road  thereto,  or  a ditch  to  convey  water  thereto,  or  a ditch  or  cut  to 
convey  the  water  therefrom,  or  without  a flume  to  carry  water  and  tail- 
ings therefrom,  or  without  a shaft  or  tunnel  thereto,  which  road,  ditch, 


LOCATION  OF  MINING  CLAIMS  ON  STATE  LANDS 


55 


cut,  flume,  or  tunnel  must  necessarily  pass  over,  under,  through,  or  across 
any  lands  or  mining  claims  owned  or  occupied  by  another,  such  owner  is 
entitled  to  a right-of-way  for  said  road,  ditch,  cut,  flume,  shaft,  or  tunnel 
over,  under,  through,  and  across  the  lands  or  mining  claims  belonging 
to  another,  upon  compliance  with  the  provisions  of  this  chapter. 

Section  7384.  Proceedings  to  Obtain  Right-of-way.  Whenever  such 
owner  desires  to  work  a mine  or  mining  claim,  and  it  is  necessary  to 
enable  him  to  do  so  successfully  and  conveniently  that  he  should  have 
a right-of-way  for  any  of  the  purposes  mentioned  in  the  foregoing  sec- 
tions ; and,  if  such  right-of-way  has  not  been  acquired  by  agreement 
between  him  and  the  owner  of  the  land  or  claims  over,  under,  across, 
and  upon  which  he  seeks  to  establish  such  right-of-way,  it  is  lawful  for 
him  to  present  to  the  judge  of  the  district  court  a complaint  asking  that 
such  right-of-way  be  awarded  to  him.  The  complaint  must  be  verified, 
and  contain  a particular  description  of  the  character  and  extent  of  the 
right  sought,  a description  of  the  mine  or  mining  claim  of  the  owner,  and 
the  mining  claim  or  claims  and  the  lands  to  be  affected  by  such  right-of- 
way,  with  the  names  of  the  occupants  or  owners  thereof,  and  may  also 
set  forth  any  tender  or  offer  hereinafter  mentioned. 

LOCATION  OF  MINING  CLAIMS  ON  STATE  LANDS. 

Section  1905.  Location  of  Mining  Claims  on  State  Lands. 

Section  1906.  Proof  of  Mineral  Character  of  Land. 

Section  1891.  Lands  Valuable  for  Stone. 

Section  1905.  Location  of  Mining  Claims  on  State  Lands.  Locations 
of  mining  claims  not  exceeding  six  hundred  (600)  feet  in  width  and 
fifteen  hundred  (1500)  feet  in  length,  each,  may  be  made  upon  lands 
belonging  to  the  State  as  follows : The  discoverer  of  a body  of  mineral 

in  either  a vein,  lode  or  ledge,  or  mineral  in  a placer  deposit,  shall 
immediately  post  conspicuously  a notice  that  he  has  made  such  a dis- 
covery, on  the  date  stated  in  such  notice,  and  shall  complete  such  location 
in  all  respects  as  prescribed  by  the  laws  of  this  State  for  the  location  of 
mining  claims  upon  the  public  lands  of  the  United  States,  except  that  no 
notice  of  such  location  need  be  recorded  in  the  office  of  the  County  Clerk, 
but  such  notice  shall  be  filed  with  the  Register  of  State ‘Lands.  Such  pro- 
cedure shall  empower  the  locator  to  retain  possession  of  and  operate  said 
claim  for  the  period  of  one  year,  at  the  end  of  which  time  he  shall  be 
required  to  purchase  said  claim  at  ten  dollars  per  acre  or  take  a lease 
thereof  at  such  price,  or  upon  such  terms  as  may  be  agreed  upon  between 
him  and  the  State  Board  of  Land  Commissioners. 

Section  1906.  Proof  of  Mineral  Character  of  Land.  Before  the  locator 
will  be  allowed  to  purchase  the  claim  located  by  him,  satisfactory  proof 
at  a hearing,  if  deemed  necessary,  must  be  submitted  to  the  State  Board 
of  Land  Commissioners,  that  such  claim  is  . more  valuable  for  mineral 
purposes  than  for  any  other  purpose,  and  that  the  same  contains  a body 
of  mineral  in  place,  or  a placer  deposit,  of  sufficient  value  to  justify  the 
operation  of  the  same  as  a present  fact ; provided,  that  no  mining  claim 
shall  be  located  upon  any  coal  or  oil  lands ; and,  provided,  further,  that 


56  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

all  hearings  under  the  provisions  of  this  section  shall  be  had  before  the 
contest  board  with  like  procedure  as  other  contested  cases;  and  provided, 
further,  that  no  lands  classified  under  Subdivision  4 of  the  classification 
in  the  constitution  shall  be  sold  as  mineral  lands,  but  the  mineral  therein 
may  be  sold  separately  from  the  surface. 

Section  1891.  Lands  Valuable  for  Stone.  Whenever  it  shall  appear 
to  the  State  Board  of  Land  Commissioners  that  there  is  a deposit  of 
stone  valuable  for  building,  mining,  or  other  commercial  purposes  upon 
any  section  or  subdivision  of  State  land,  the  Board  shall  not  lease  the 
same  for  any  purpose  except  for  the  extraction  and  working  of  the  stone 
and  then  upon  a royalty  basis  only,  upon  such  terms  as  the  Board  shall 
prescribe.  The  Board  may  lease  the  remainder  of  the  section  or  sub- 
division for  agriculture,  grazing  or  other  purposes,  as  may  appear  for  the 
best  interests  of  the  State,  as  other  State  lands  are  leased ; but  shall 
provide  in  all  such  cases  for  a right  of  way  across  said  State  land  or  any 
adjoining  State  land  for  all  purposes  connected  with  the  working  and 
disposition  of  the  stone. 


SALE,  LEASES  AND  RENTALS  OF  STATE  LANDS. 

REVISED  CODES  1921. 


Section  1846. 
Section  1852. 

Section  1882. 
Section  1883. 
Section  1890. 


Coal  Lands — What  Deemed — Selection. 

Sale  of  State  Lands — Reservation  of  Coal,  Oil 
and  Gas. 

Leasing  of  Land. 

Lands — How  Leased. 

Rental  of  Coal  Lands. 


Section  1846.  Coal  Lands — What  Deemed — Selection.  All  coal  areas  in 
the  State  after  final  examination  are  defined  by  the  United  States 
geological  survey,  or  other  authority  under  the  government  of  the  United 
States,  shall  be  recognized  by  the  authorities  of  this  State  as  coal  lands, 
until  otherwise  determined ; and  no  such  lands  shall  be  sold,  but  such 
lands  may  be  leased  by  the  State  to  any  person  or  persons,  company  or 
corporation,  but  only  on  a royalty  basis  as  herein  provided ; provided, 
however,  that  the  surface  rights  of  such  land  may  be  sold  or  may  be  leased 
for  either  agricultural  or  grazing  purposes,  but  any  other  State  lands 
may  he  designated  as  coal  lands  by  the  State  Board  of  Land  Commis- 
sioners, and  withdrawn  from  sale  when,  in  the  opinion  of  the  Board,  such 
lands  contain  coal. 

Section  1852.  Sale  of  State  Lands — Reservation  of  Coal,  Oil  and  Gas. 

The  State  Board  of  Land  Commissioners  may  direct  the  sale  of  any 
State  lands,  except  as  provided  in  this  act,  * * * and,  provided, 
further,  that  all  leases  and  conveyances  of  State  lands  by  the  State  Board 
of  Land  Commissioners  shall  contain  a reservation  to  the  State  of  all 
coal,  oil  and  gas  contained  therein. 

Section  1882.  Leasing  of  Land.  The  State  Board  of  Land  Commis- 
sioners may  lease  any  portion  of  the  land  of  the  state  at  a rental  to  be 
determined  after  an  examination  of  the  land  by  an  appraiser,  except  as 


SALE,  LEASES  AND  RENTALS  OF  STATE  LANDS 


57 


herein  provided.  The  lessee  shall  pay  the  annual  rental  in  advance  to 
the  Register  of  State  Lands,  who  shall  receipt  for  the  same.  If  stone, 
coal,  coal-oil,  gas,  or  other  mineral  not  mentioned  herein,  be  found  upon 
the  state  land,  such  land  must  be  leased  only  for  the  purpose  of  obtaining 
therefrom  the  stone,  coal,  coal-oil,  gas,  or  other  mineral,  for  such  length 
of  time,  and  conditional  upon  the  payment  to  the  register  of  such  royalty 
upon  the  product  as  the  State  Board  of  Land  Commissioners  may  de- 
termine. 

Section  1883.  Lands,  How  Leased,  At  every  public  sale  of  state  lands, 
each  tract  of  land,  except  timber  lands,  for  which  no  bid  for  its  purchase 
has  been  received,  shall  be  immediately  offered  for  lease  to  the  highest 
bidder,  as  follows:  By  quarter-sections,  or  so* much  thereof  as  belongs  to 

the  state,  in  the  case  of  lands  classified  as  agricultural  (a)  ; by  half- 
sectiions,  in  the  case  of  lands  classified  as  agricultural  (b)  ; and  by  sec- 
tions in  the  case  of  lands  classified  as  grazing;  and  smaller  tracts  shall 
not  be  leased,  unless  it  is  deemed  impossible  to  lease  as  above  described, 
or  unless  a larger  price  may  be  obtained  thereby ; and  no  land  shall  be 
leased  for  a longer  period  than  five  years,  nor  for  a less  rental  than  the 
minimum  rental  fixed  by  the  board,  which  shall  not  be  less  than  five 
per  centum  per  annum  of  the  appraised  value  of  such  lands. 

Section  1890.  Rental  of  Coal  Lands.  Any  person,  association,  co- 
partnership or  corporation,  leasing  and  operating  coal  land  under  the 
provisions  of  this  act,  shall  pay  to  the  State  the  minimum  price  of  not 
less  than  ten  (10)  cents  per  ton  for  each  and  every  ton  of  merchantable 
coal  so  mined  from  said  land,  to  be  paid  monthly  on  or  before  the  25th 
day  of  each  month,  for  the  coal  mined|  during  the  preceding  calendar 
month.  Should  the  lessee  of  such  coal  land  fail  to  mine  during  any  one 
year  the  minimum  amount  that  may  be  provided  for  in  the  term  of  the 
lease,  he  shall,  notwithstanding  such  failure,  pay  to  the  State  the  mini- 
mum rental  provided  for  in  said  lease.  Should  any  person  apply  to  lease 
any  of  the  coal  lands  belonging  to  the  State,  upon  which  there  are  surface 
or  underground  improvements  placed  or  made  by  a former  lessee,  before 
a lease  shall  issue,  said  applicant  shall  file  in  the  office  of  the  Register 
a receipt  showing  that  the  price  of  said  improvements,  as  agreed  upon 
by  the  parties,  or  fixed  by  the  State  Land  Agent,  or  one  of  his  assistants, 
has  been  paid  to  the  owner  thereof  in  full,  or  shall  make  satisfactory 
proof  that  he  has  tendered  to  such  owner  the  price  of  such  surface  or 
underground  improvements  so  agreed  upon  or  fixed ; or  proof  that  the 
owner  of  such  improvements  elects  to  remove  them. 


58 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


MINING  PARTNERSHIPS. 

REVISED  CODES  1921. 


Section  8050. 
Section  8051. 
Section  8052. 
Section  8053. 
Section  8054. 
Section  8055. 
Section  8056. 
Section  8057. 
Section  8058. 
Section  8059. 


When  a Mining  Partnership  Exists. 

Express  Agreement  Not  Necessary. 

Profits  and  Losses,  How  Shared. 

Liens  of  Partners. 

Mine-Partnership  Property. 

Partnership  Not  Dissolved  by  Sale  of  Interest 
Purchaser  Takes  Subject  to  Liens. 

Takes  With  Notice  of  Lien,  When. 

Contract  in  Writing — When  Binding. 

Owners  of  Majority  of  Shares  Govern. 


Section  8050.  When  a Mining  Partnership  Exists.  A mining  partner- 
ship exists  when  two  or  more  persons  who  own  or  acquire  a mining  claim 
for  the  purpose  of  working  it  and  extracting  the  mineral  therefrom, 
actually  engage  in  working  the  same. 

Section  8051.  Express  Agreement  Not  Necessary.  An  express  agree- 
ment to  become  partners  or  to  share  the  profits  and  losses  of  mining  is 
not  necessary  to  the  formation  and  existence  of  a mining  partnership. 
The  relationship  arises  from  the  ownership  of  shares  or  interests  in  the 
mine  and  working  the  same  for  the  purpose  of  extracting  the  minerals 
therefrom. 

Section  8052.  Profits  and  Losses,  How  Shared.  A member  of  a mining 
partnership  shares  in  the  profits  and  losses  thereof  in  the  proportion 
which  the  interest  or  share  he  owns  in  the  mine  bears  to  the  whole  part- 
nership capital  or  whole  number  of  shares. 

Section  8053.  Liens  of  Partners.  Each  member  of  a mining  partner- 
ship has  a lien  on  the  partnership  property  for  the  debts  due  the  creditors 
thereof,  and  for  money  advanced  by  him  for  its  uses.  This  lien  exists 
notwithstanding  there  is  an  agreement  among  the  partners  that  it  must 
not. 


Section  8054.  Mine  is  Partnership  Property.  The  mining  ground  owned 
and  worked  by  partners  in  mining,  whether  purchased  with  partnership 
funds  or  not,  is  partnership  property. 

Section  8055.  Partnership  Not  Dissolved  by  Sale  of  Interests.  One 

of  the  partners  in  a mining  partnership  may  convey  his  interest  in  the 
mine  and  business  without  dissolving  the  partnership.  The  purchaser, 
from  the  date  of  his  purchase,  becomes  a member  of  the  partnership. 

Section  8056.  Purcliaser  Takes  Subject  to  Liens.  A purchaser  of  an 
interest  in  the  mining  ground  of  a mining  partnership  takes  it  subject  to 
the  liens  existing  in  favor  of  the  partners  for  debts  due  all  creditors 
thereof,  or  advances  made  for  the  benefit  of  the  partnership,  unless  he 
purchased  in  good  faith,  for  a valuable  consideration,  without  notice  of 
such  lien. 

Section  8057.  Purchaser  Takes  With  Notice  of  Lien,  When.  The 
purchase  of  the  interest  of  a partner  in  a mine  when  the  partnership  is 


SAFETY  TO  UNDERGROUND  MINERS 


59 


engaged  in  working  it,  takes  with  notice  of  all  liens  resulting  from  the 
relationship  of  the  partners  to  each  other,  and  to  the  creditors  of  the 
partnership. 

Section  8058.  How  Partnership  Bound.  No  member  of  a mining  part- 
nership or  other  agent  or  manager  thereof  can,  by  a contract  in  writing, 
bind  the  partnership,  except  by  express  authority  derived  from  the  mem- 
bers thereof. 

Section  8059.  Majority  of  Shares  Governs.  The  decision  of  the  mem- 
bers owning  a majority  of  the  shares  or  interests  in  a mining  partnership 
binds  it  in  the  conduct  of  its  business. 


FRAUD  IN  SELLING  MINES,  ETC. 

Section  11419.  Uses  of  False  Pretenses  in  Selling  Mines. 
Section  11420.  Interference  With  Samples  for  Assay. 
Section  11421.  Making  False  Samples  of  Ore. 


Section  11419.  False  Pretenses  in  Selling  Mines.  Every  person  who, 
with  intent  to  cheat,  wrong,  or  defraud,  places  in  or  upon  any  mine  or 
mining  claim  any  ores  or  specimens  of  ores  not  extracted  therefrom,  or 
exhibits  any  ore,  or  certificate  of  assay  of  ore  not  extracted  therefrom, 
for  the  purpose  of  selling  any  mine  or  mining  claim,  or  interest  therein, 
or  who  obtains  any  money  or  property  by  any  such  false  pretenses  or 
artifices,  is  guilty  of  a felony. 

Section  11420.  Interference  With  Samples  for  Assay.  Every  person 
who  interferes  with,  or  in  any  manner  changes  samples  of  ores  or  bullion 
producing  for  sampling  or  changes  or  alters  samples  or  packages  of  ores 
or  bullion  which  have  been  purchased  for  assaying,  or  who  shall  change 
or  alter'  any  certificate  of  sampling  or  assaying,  with  intent  to  cheat, 
wrong,  or  defraud,  is  guilty  of  a felony. 

Section  11421.  Making  False  Samples  of  Ores.  Every  person  who, 
with  intent  to  cheat,  wrong,  or  defraud,  makes  or  publishes  a false 
sample  of  ore  or  bullion,  or  who  makes  or  publishes,  or  causes  to  be 
published  a false  assay  of  ore  or  bullion  is  guilty  of  a felony. 


SAFETY  TO  UNDERGROUND  MINERS. 

REVISED  CODES  1921. 


Section  11269. 
Section  11270. 
Section  11271. 
Section  11273. 
Section  11274. 
Section  11275. 
Section  3434. 


Stoping  Near  Shaft. 

Running  Cage  at  Excessive  Speed. 
Maintaining  Buildings  Near  Mouth  of  Shaft. 
Escapement  Shaft. 

To  What  Mines  Act  Applicable. 

Penalty. 

Protections  and  Guard-rails  in  Case  of  Shafts 
and  Underground  Openings. 


Section  11269.  Stoping  Near  Shaft.  It  is  unlawful  for  any  corporation 
or  person  operating  any  mine  in  this  State  worked  through  a vertical  or 
incline  shaft  to  stope  within  a less  distance  than  twenty-five  (25)  feet 
of  the  said  shaft  when  other  work  is  being  carried  on  below  said  stoping. 


60  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

Section  11270.  Running  Cage  at  Excessive  Speed.  It  is  unlawful  for 
any  person  or  corporation  operating  any  mine  in  this  State  worked 
through  a vertical  or  incline  shaft,  where  a cage  or  other  device  is  used 
for  the  purpose  of  hoisting  or  lowering  men,  to  run  such  cage  when  men 
are  upon  the  same  at  a greater  speed  than  eight  hundred  (800)  feet  per 
minute. 

Section  11271.  Maintaining  Buildings  Near  Mouth  of  Shaft.  It  is 

unlawful  for  any  person,  company  or  corporation  to  erect  or  maintain 
any  building  or  inclosure,  used  for  a blacksmith  shop  or  drying  room 
within  a distance  of  fifty  (50)  feet  of  the  mouth  of  any  tunnel  or  shaft, 
unless  the  same  be  fire-proof  in  its  construction. 

Section  11273.  Escapement  Shaft.  It  is  the  duty  of  any  person,  company 
or  corporation,  who  shall  have  sunk  on  any  mine  a vertical  or  incline 
shaft  to  a greater  depth  than  one  hundred  feet,  and  who  shall  have  the 
top  of  such  shaft  or  hoisting  opening  covered  or  enclosed  by  a shaft 
or  building  which  is  not  fire-proof,  and  who  shall  have  drifted  on  or  along 
the  vein  or  veins  thereof,  a distance  of  two  hundred  feet  or  more,  after 
cross  cutting  to  the  same,  and  shall  have  commenced  to  stope,  to  provide 
and  maintain  to  the  hoisting  shaft  or  the  opening  through  which  men 
are  let  into  or  out  of  the  mine  and  the  ore  is  extracted,  a separate  escape- 
ment shaft,  raise,  or  opening,  or  an  underground  opening  or  communica- 
tion between  every  such  mine  and  some  other  contiguous  mine,  provided, 
that  in  case  such  contiguous  mine  belongs  to  a different  person,  company 
or  corporation,  the  right  to  use  the  outlet  through  such  contiguous  mine 
in  all  cases  when  necessary,  or  in  cases  of  accident,  must  be  secured  and 
kept  in  force.  Where  such  an  escapement  shaft  or  opening  shall  not  be 
in  existence  at  the  time  that  stoping  is  commenced,  work  upon  such 
escapement  shaft  or  opening  must  be  commenced  as  soon  as  stoping  be- 
gins and  be  diligently  prosecuted  until  the  same  is  completed,  and  said 
escapement  shaft,  raise  or  opening  shall  be  continued  to  and  connected 
with  the  lowest  workings  in  the  mine.  The  exit,  escapement  shaft,  raise 
or  opening  provided  for  in  the  foregoing  paragraphs  must  be  of  sufficient 
size  as  to  afford  an  easy  passage  way  and  if  it  be  a raise,  or  shaft, 
must  be  provided  with  good  and  substantial  ladders  from  the  deepest 
workings  to  the  surface.  Whenever  the  exit  or  outlet  herein  provided 
for  is  not  a direct  or  continuous  course,  signboards  plainly  marked  show- 
ing the  direction  to  be  taken  must  be  placed  at  each  departure  from  the 
continuous  course. 

Section  11274.  To  What  Mines  Act  Applicable.  This  Act  shall  apply 
only  to  quartz  mines  in  which  nine  or  more  men  are  employed  under- 
ground, and  shall  not  apply  to  mines  not  actually  extracting  ores,  by 
stoping,  nor  to  mines  in  which  the  shaft  or  hoisting  opening,  or  hauling 
way  is  not  covered  by  a shaft  house,  and  has  no  building  structure  within 
thirty  (30)  feet  of  the  shaft  or  opening  nor  to  mines  in  which  the  hoisting 
shaft  or  opening  shall  be  covered  by  or  enclosed  in  a fire-proof  shaft  or 
building. 

Section  11275.  Penalty.  Every  person  or  corporation  failing  to  comply 
with  any  of  the  above  sections  punishable  by  a fine  of  not  less  than 
three  hundred  dollars  nor  more  than  one  thousand  dollars. 


CODE  OF  SIGNALS  IN  METAL  MINES 


61 


Section  3434.  Protections  and  Guard-rails  in  Case  of  Shafts  and 

Underground  Openings.  Underground  workings  consisting  of  chutes, 
manways,  and  winzes,  or  any  openings  kept  for  ventilating  purposes,  or 
for  the  removal  of  ore  or  waste  material,  shall  when  necessary  be  pro- 
tected by  guard-rails,  or  by  a suitable  cover  known  as  a grizzly,  made  of 
good,  substantial  timbers  or  metal  bars.  Shafts  at  stations  shall  be  pro- 
tected by  guard-rails  at  every  level.  In  vertical  manways  used  by 
employes  exclusively  for  traveling  purposes,  in  addition  to  proper  ladders 
there  shall  be  suitable  landings,  placed  not  to  exceed  thirty  feet  apart, 
and  so  far  as  feasible  and  practicable  all  such  manways  or  air-courses 
used  as  an  escape  for  men  must  be  kept  free  from  all  obstructions. 

CODE  OF  SIGNALS  IN  METAL  MINES. 

REVISED  CODE  1921. 

Section  3429.  Code  of  Signals  in  Metal  Mines. 

Section  3430.  Penalties. 

Section  3429.  Signals  of.  It  is  made  the  duty  of  the  inspector  of  mines 
of  Montana,  and  he  is  hereby  required  to  prepare  a complete  code  of 
signals  for  the  use  in  all  mines  in  this  state,  worked  through  a shaft  of 
seventy-five  feet  or  more  in  depth,  and  employing  ten  or  more  men,  and 
cause  the  same  to  be  made  known  to  each  owner  or  operator  of  a mine 
in  Montana  by  printed  circular  instructions,  to  the  end  that  a uniform 
code  of  mine  signals  may  prevail.  The  said  inspector  of  mines  of  Mon- 
tana may  add  to  or  change  such  code  of  signals  as  circumstances  may 
require,  but  no  change  of  signals  shall  go  into  effect  until  a time  specified 
by  him,  not  less  than  sixty  days  nor  more  than  ninety  days  from  the 
time  such  change  shall  be  ordered  by  him ; provided,  that  the  code  of 
signals  first  prepared  by  him  shall  be  used  in  all  said  shaft  mines  from 
and  after  June  1,  1895. 

Section  3430.  Penalties.  Any  owner  or  operator  of  a mine  who  shall 
refuse  or  neglect  to  cause  the  signals  provided  for  in  the  preceding  section 
to  be  used  in  his  mine,  to  the  exclusion  of  all  other  signals,  shall  be 
deemed  guilty  of  a misdemeanor,  and  upon  conviction  of  such  refusal  or 
neglect  shall  be  fined  in  a sum  not  less  than  one  hundred  dollars  nor 
more  than  five  hundred  dollars,  or  by  imprisonment  in  the  county  jail 
for  a period  of  not  less  than  thirty  days  or  more  than  ninety  days,  in 
the  discretion  of  the  court,  for  each  and  every  offense. 

STATE  CODE  OF  MINE  SIGNALS. 

Signal  Bells. 

1 bell  hoist,  1 bell  stop  (if  in  motion). 

2 bells  lower  men,  3 bells  hoist  men. 

4 bells  blasting  signal,  engineer  must  answer  by  raising  bucket  a few 
feet  and  letting  it  back  slowly. 

Then  one  bell  hoist  men  away  from  blast. 

5 bells  steam  on,  6 bells  steam  off. 

7 bells  air  on,  8 bells  air  off.  3-2-2  send  down  drills.  3-2-3  sencl  down 

picks. 


62  MONTANA*  STATE  BUREAU  OF  MINES  AND  METALLURGY 

9 bells  danger  signal  (case  of  fire  or  other  danger),  then  ring  number 
of  station  where  danger  exists.  No  person  shall  ring  any  bell  except  the 
station  tender,  except  in  case  of  danger,  or  when  the  main  shaft  is  being 
sunk.  Engineers  must  slow  up  wThen  passing  stations  when  men  are  on 
cage. 

Station  Bells. 


Bells  Pause 

Bells 

No.  Station 

Bells 

Pause 

Bells 

No.  Station 

2 

1 

1 

5 

a 

4 

19 

2 “ 

2 

2 

5 

a 

5 

20 

2 “ 

3 

3 

6 

it 

1 

21 

2 

4 

4 

6 

it 

2 

22 

2 “ 

5 

5 

6 

if 

3 

23 

3 

1 

6 

6 

a 

4 

24 

3 

2 

7 

6 

it 

5 

25 

3 

3 

8 

7 

it 

1 

26 

3 

4 

9 

7 

a 

2 

27 

3 

5 

10 

7 

a 

3 

28 

4 

1 

11 

7 

a 

4 

29 

4 

2 

12 

7 

a 

5 

30 

4 

3 

13 

8 

a 

1 

31 

4 

4 

14 

8 

a 

2 

32 

4 

5 

15 

8 

a 

3 

33 

5 

1 

16 

8 

a 

4 

34 

5 

2 

17 

8 

a 

5 

35 

5 

3 

18 

9 

a 

1 

36 

Where  electric  bells 

are  used  in  connection 

with  other  bells. 

If  cage  is  wanted  ring  station  signal.  Station  tender  will  answer  1 bell. 

Reply  1 bell  to  go  up. 

Reply  2 bells  to  go  below. 

If  station  is  full  of  ore  and  station  tender  is  wanted,  ring  station  signal 
and  do  not  answer  back. 

If  2-1-2  bells  are  rung,  engineer  or  station  tender  does  not  understand, 
repeat  signal. 

In  case  of  danger  or  accident,  ring  station  signal,  station  tender  will 
reply  1 bell,  ring  9 bells. 

One  copy  of  this  code  should  be  posted  on  the  gallows  frame  and  one 
before  the  engineer. 

To  be  in  effect  from  and  after  June  1st,  1895. 

This  code  is  subject  to  change  under  certain  conditions. 


. PROCEDURE  TO  EXAMINE  ADJOINING  MINING 

PROPERTIES 

REVISED  CODE  1921. 

Section  9494.  Whenever  any  person  shall  have  any  right  to  or  interest 
\n  any  lead,  lode,  or  mining  claim  which  is  in  the  possession  of  another 
person,  and  it  shall  be  necessary  for  the  ascertainment,  enforcement,  or 
protection  of  such  right  or  interest  that  an  inspection,  examination,  or 
survey  of  such  lead,  mine,  lode,  or  mining  claim  should  be  had  or  made ; 
or  whenever  any  inspection,  examination,  or  survey  of  any  such  lode  or 
mining  claim  shall  be  necessary  to  protest,  ascertain,  or  enforce  the  right 
or  interest  of  any  person  in  another  mine,  lode,  or  mining  claim,  and  the 
person  in  possession  of  the  same  shall  refuse,  for  a period  of  three  days 
after  demand  therefore  in  writing,  to  allow  such  inspection,  examination, 
or  survey  to  be  had  or  made,  the  party  so  desiring  the  same  may  present 
to  the  district  court,  or  judge  thereof,  of  the  county  wherein  the  mine, 
lead,  lode,  or  mining  claim  is  situated,  a petition,  under  oath,  setting  out 
his  interest  in  the  premises,  describing  the  same  that  the  premises  are  in 
the  possession  of  a party,  naming  him,  the  reason  why  such  examination, 
inspection,  or  survey  is  necessary,  the  demand  made  on  the  person  in 
possession  so  to  permit  such  examination,  inspection,  or  survey,  and  his 
refusal  so  to  do.  The  judge  or  court  shall  thereupon  appoint  a time  and 
place  for  hearing  such  petition,  and  shall  order  notice  thereof  to  be  served 
upon  the  adverse  party,  which  notice  shall  be  served  at  least  one  day  be- 
fore the  day  of  hearing.  On  the  hearing  either  party  may  read  affidavits 
or  produce  oral  testimony  and  if  the  court  or  judge  is  satisfied  that  the 
facts  stated  in  the  petition  are  true,  he  shall  make  an  order  for  an  in- 
spection, examination,  or  survey  of  the  lode  or  mining  claim  in  question, 
in  such  manner,  at  such  time,  and  by  such  persons  as  are  mentioned  in  the 
order  Such  person  shall  thereupon  have  free  access  to  such  mine,  lead, 
lode,  or  mining  claim  for  the  purpose  of  making  such  inspection,  examina- 
tion, or  survey,  and  any  interference  with  such  person  while  acting  under 
such  order  shall  be  contempt  of  court.  If  the  order  of  the  court  is  made 
while  an  action  is  pending  between  the  parties  to  the  order,  the  costs 
of  obtaining  the  order  shall  abide  in  the  result  of  the  action,  but  all  costs 
of  making  such  examination  or  survey  shall  be  paid  by  the  petitioner. 


— 63  — 


DESTROYING  NOTICES---PENALTY 

REVISED  CODES. 

Section  11491.  Every  person  who  intentionally: 

1.  Defaces,  obliterates,  tears  down  or  destroys  any  copy  or  transcript  or 
extract  from  or  of  any  law  of  the  United  States  or  of  this  State,  or  any 
proclamation,  advertisement  or  notification  set  up  at  any  place  in  this 
State  by  authority  of  any  law  of  the  United  States  or  of  this  State  or  by 
order  of  any  court,  before  the  expiration  of  the  time  for  which  the  same 
was  to  remain  set  up ; or, 

2.  Defaces,  obliterates,  tears  or  destroys  any  notice  placed  or  posted 
on  a mining  claim,  or  removes  or  destroys  any  stake  or  monument  placed 
thereon  to  identify  it, 

Is  punishable  by  imprisonment  in  the  county  jail  not  exceeding  three 
months  or  by  a fine  not  exceeding  one  hundred  dollars,  or  both. 


INDEX 


A 

Page 

Abandonment  22 

Acquired  Interests  Under  Leasing  Act  40 

Act  of  Feb.  25,  1920 - 38 

Adjoining  Properties,  Examination  of 63 

Advertising  Out  21 

Adverse  Claim  - 26 

Agent  9 

Agricultural  Land 8 

Aliens  9,  39 

Amended  Location V 22,  53,  54 

Amended  Certificate  of  Location 22,  54 

Annual  Labor  20,  52 

Act  of  Aug.  24,  1921 20 

Affidavit  of : j 21,  52 

On  Group  of  Claims , 20 

On  Tunnel  Claim 36 

Apex  28 

Application  for  Patent , 23 

Application  for  Permits  and  Leases  for  Oil,  Gas,  Coal,  etc 40 

Area  of  Coal  Lease 1 42 

Area  of  Lode  Claim 15 

Area  of  Oil  and  Gas  Leases 46 

Area  of  Oil  Shale  Lease 48 

Area  of  Phosphate  Lease 44 

Area  of  Placer  Claim.... 29 

Area  of  Sodium  Lease 49 

Assessment  Work  20 

Assigning  of  Leases 41 

Associations  - 9 

B 

Boundaries,  Marking  of 14,  50 

Brick  Clay  10 

C 

Cancellation  of  Permits 40 

Certificate  of  Location 17,  51 

Certificate  of  Amended  Location 22 

Citizens  9,  23,  39 

Claims : 

Coal  42 

Gas  45 

Lode  10,  12,  50 

Oil  45 

Oil  Shale  48 

Phosphate  - - 44 

Placer  29 

Quartz  10,  12 

Sodium  49 

Stone  12,  56 

Tunnel  10,  35,  36 

Clay  10 

— 65  — 


66  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

Coal : Page 

On  State  Land 11,  56 

Rental  of  State  Coal  Land r. 57 

On  Government  Land 38,  42 

Coal  Lands : 

Under  Act  of  Feb.  25,  1920 42 

Area  Leased  „ : 42 

Consolidation  of  Leases 43 

Leasing  of  - 42 

Leases  to  Cities * 43 

Leases  on  Land  Occupied 43 

Method  of  Leasing  42 

Period  of  Lease 43 

Permits  and  Lease  42 

Railroads  42 

Royalties  and  Rentals 43 

Code  of  Montana  1921 50-55 

Code  of  Signals  in  Metal  Mines - 61 

Combined  Interests  in  Leasing  Act 40 

Co-owner  21 

Corners  of  Claims . .— . 14,  50 

Destroying  of,  Penalty 64 

Corporations  — ~ - - 9,  39 

D 

Defective  Locations  53 

Definitions : 

Apex  28 

Contiguous  - 11 

Face  11 

Lead  ^ - 10 

Ledge  - - 10 

Lode  10 

Mineral  Land  7 

Outcrop  28 

Vein  10 

Destroying  Notices,  Penalty .> ~ 64 

Discovery  12,  50 

Discovery  Cut  or  Tunnel 17 

Discovery  Shaft  17,  50 

Discovery  Work  17 

E 

Effect  of  Patent 54 

End  Lines  : 15 

Escapement  Shaft  60 

Examination  of  Adjoining  Properties..... 63 

Extra  Lateral  Rights  -- 27 

For  Vein  in  Placer  Claim 35 

F 

Forms  for : 

Application  for  Patent 25 

Certificate  of  Location 18 

Certificate  of  Placer  Location 32 

Notice  of  Location 13,  14 

Placer  Location  31 

Survey  : 25 

Forfeiture  - 21 

Forfeiture  of  Co-owners’  Interest 21 

Fraud  in  Selling  Mines 59 


INDEX 


67 


G 

Page 

Gas  (See  Oil  and  Gas),  Government  Land 38,  45 

On  State  Land 56 

Guard-rails  for  Shafts  and  Openings 61 

Gulch  Placers , ' 30 

H 

Helium  ; 48 

I 

Indian  Reservations  7 

Open  to  Location 4 8 

L 

Labor  on  Tunnel  Claims 36 

Lands  Subject  to  Location 7 

State  Lands  55 

Leasing  Act  of  Feb.  25,  1920 : 

Lands  Affected  * 38 

Permits  and  Lease 39 

Right  of  Aliens 39 

Leasing  of  Government  Coal  Lands 42 

Leasing  of  State  Coal  Lands 56 

Leasing  of  Oil,  Gas,  Coal,  Phosphate,  Oil  Shale 38 

Ledge,  Definition  of 10 

Locations : 

By  Citizens  : 9 

By  Aliens  9 

By  Agent  9 

By  Minor  p 

By  Government  Officials  9 

Number  Allowed  9 

Location  on  Forest  Reserve 7 

Location  of  Lode  Claims : 12,  50 

On  Government  Land  7 

On  State  Land 7,  55 

On  Indian  Reservations 7 

On  School  Lands 8 

In  Public  Parks  7 

On  Agricultural  Land 8 

Location  Notice  13,  50 

Location  Corners 14,  51 

Location  of  Placer  Claim 29 

Location  of  Tunnel  Claim 35 

Locations,  Validation  of 53 

Lode,  Definition  of . 10 

Lode  Claim  10,  12,  50 

Lode,  on  Placer  Claim 34 

Lode,  Size  of 15 

Lode  Claims  Over  Tunnel 36 

M 

Marking  Location 14,  50 

Millsites : 

Definition  of 11 

Location  of 37,  52 

Form  of  Location  Notice 37 

Patenting  of 37 

Mine  Buildings  Near  Shaft  or  Tunnel 60 

Mine  Cages,  Speed  of 60 

Mine  Signals  : 61.  62 


68 


MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 


Page 

Mineral  Land,  Definition 7 

Mineral  Surveyor 9 

Mining  Partnerships  1 58 

Mining  Claims  on  State  Land 55 

Mining  Laws  of  Montana,  Revised  Code  1921 50-57 

Montana  Code  of  1921  as  to  Claims , 50,  56 

N 

Notice  of  Location 13,  50 

Posting  of 14,  50 

Destroying  of 64 

Number  of  Locations  Allowed : 9 

O 

Oil: 

On  Government  Land 11,  45 

On  State  Land 11,  56 

Oil  and  Gas  Lands 45 

Description  of  Lands 46 

Dimensions  of  Land  45 

Discovery  of  Oil  and  Gas 46 

Helium  48 

Lease  on  Land  Having  Oil  and  Gas  Reserved 47 

Leasing  of  Lands  in  Producing  Oil  and  Gas  Field 47 

Life  of  Lease 47 

Location  of  Wells - * 46 

Permit  for  Unappropriated  Lands 45 

Permit  in  Known  Field 45 

Preference  Right  to  Permit •. 45 

Precautions  When  Drilling .7. 46 

Preference  Right  of  Owner  of  Surface 47 

Reduction  of  Royalty 47 

Royalties  and  Rentals  47 

Royalty  Prior  to  Lease 46 

Terms  and  Conditions  of  Permit 45 

Work  Required - 46 

Oil  Shale  Lands 48 

Claims  Held  Under  Former  Laws 48 

Period  of  Lease - 48 

Royalties  and  Rentals 48 

Size  of  Lease 48 

Overlapping  Locations 17 

Outcrop : 

Definition  of 28 

Illustration  of 28,  29 

P 

Patent : Effect  of 23,  27,  54 

Patent : Statute  of  Limitations 8 

Partnerships,  Mining  - 58 

Patenting  Lode  Claim 23 

Permits  for  Coal,  Phosphate,  Oil.  Gas,  Oil  Shale,  and  Sodium 39 

Permits  for  Land  with  Mineral  Right  Reserved 40 

Phosphate  Lands 44 

Pipe  Lines  for  Oil  or  Gas 41 

Placer  Claim 10,  29,  52 

Annual  Labor 34 

Discovery  Work 29,  34 


INDEX 


69 


Placer  Location 

Form  for 

Shape  of 

Size  of 


Page 
.29,  52 

31 

30 

29 


R 

Railroads  

Register’s  Certificate 

Relinquishment  of  Lease 

Relocation  

Representation  Work 

Revised  Code  of  Montana 

Revised  Statutes  of  United  States : 

Section  2319 

Section  2320 

Section  2322 

Section  2323 

Section  2324,  Amendment  to 

Section  2325 

Section  2326 

Section  2329^ 

Section  2331 

Section  2333 

Section  2336 

Section  2337 

Rights  of  Relocator 

Right  of  Way  for  Pipe  Lines 

Right  of  Way  for  Road  or  Ditch 

Proceedings  for 


42 

20,  24 

41 

22,  52 

20,  52 

.50,  55,  56,  58,  59,  61,  63,  64 


7 

15 

29 
10 
36 
24 
26 

30 
30 
34 
29 
11 

53 
41 

54 

55 


S 

Safety  to  Underground  Miners,  Revised  Codes  1921 59 

School  Lands 8 

Selling  Mines,  Fraud  in 59 

Shape  of  Lode  Claims 15 

Shaft,  Discovery  17,  51 

Shaft  for  Escapement....... 60 

Shaft,  Protection  and  Guard-rails  for 61 

Signals  in  Metal  Mines 61 

Size  of  Claims  (Lode) 15 

Placer  Claims 29 

Tunnel  Claims 10,  35 

Sodium  Lands 49 

Additional  Land^.~ 49 

Known  Deposits 49 

Lease  49 

Permit  - 49 

Period  of  Lease 49 

Rental  49 

Royalty  49 

State  Lands 7,  11,  55 

Leasing  of 56 

How  Leased 57 

Coal  on 11,  56 

Sale  of 56 

Statute  of  Limitations  for  Patent 8 

Stone  Claims : 12,  56 


70  MONTANA  STATE  BUREAU  OF  MINES  AND  METALLURGY 

Page 

Stoping  Near  Shaft 59 

Sub-Leasing  Under  Leasing  Act . 41 

Surface  Rights  on  Leased  Government  Lands 41 

T 

Tunnel  Claim . T 10,  35 

Labor  on . 36 

Patent  for 36 

Timber  Act  of  June  4,  1897 ~ 38 

Timber  Lands 38 

U 

Unappropriated  Land 7 

Underground  Openings,  Protection  for 61 

Unlawful  Rights  of  Persons  or  Corporations 39 

V 

Valid  Location 7 

Validating  Locations  Heretofore  Made 53 

Vein,  Apex  of 28 

Vein  Defined 10 

Vein  on  Placer  Claim 34 

Verification  of  Location  Certificate ~ 19 

W 

Working  Deposits  Covered  by  Government  Leasing  Act 41 


STATE  OF  MONTANA 

M.  A.  Brannon,  Chancellor , The  University  of  Montana 


BUREAU  OF  MINES  AND  GEOLOGY 

Francis  A.  Thomson,  Director 


Montana  Bureau  of  Mines  and  Geology  Bulletin 

ISSUED  QUARTERLY— PRICE  50  CENTS 

No.  6 January,  1931 


GEOLOGY  AND  ORE  DEPOSITS  OF 
BANNACK  AND  ARGENTA, 
MONTANA 


&2/ 


Philip  J.  Shexon 


OCT 1 7 1932 


UNIVERSITY  OF  ILLINOIS. 


MONTANA  SCHOOL  OF  MINES 

BUTTE,  MONTANA 

Entered  as  second  class  matter  January,  1931.  at  the  postoffice  at  Butte,  Montana, 
under  the  Act  of  March  3,  1879. 


\ D Lx. 


CONTENTS 


Page 

Preface  6 

Summary 7 

Introduction  8 

Purpose  and  scope  of  the  report  8 

Acknowledgments  8 

Geography  : 10 

Situation  10 

Topography  - 10 

Climate  and  vegetation  12 

Bibliography  - - 13 

The  Bannack  area  14 

General  geology  14 

Character  and  distribution  of  the  rocks  14 

Carboniferous  system  14 

Madison  formation  14 

Quadrant  formation  15 

Mesozoic  system  16 

“Red  Beds”  ... 16 

Tertiary  gravels  17 

Auriferous  gravels  18 

Intrusive  igneous  rocks  18 

Granodiorite  18 

Petrography  10 

Exomorphic  contact  effects  21 

Age  22 

Basic  dikes  22 

Extrusive  igneous  rocks  22 

Distribution  and  thickness  22 

Andesite  23 

General  character  23 

Petrography  23 

Dacite  23 

General  character  24 

Petrography  24 

Rhyolite  24 

Basalt  25 

Age  of  the  volcanic  rocks  25 

Deformation  25 

Folding  25 

Faulting  25 

Ore  deposits  26 

Historical  sketch  of  mining  26 

Production  + - 27 

Mineralogy  of  the  ore  28 

Ore  minerals  29 

Gangue  minerals  - 31 

Blue  Wing  mining  district  32 

Kent  mine  32 

Del  Monte  mine  - 34 

New  Departure  mine  - 36 

Huron  mine  37 


4 


CONTENTS 


The  Bannack  area  (continued) 

Pomeroy  mine  

Randall  mine  Z""Z*Z" 

Silver  Star  mine  

Ingersoll  mine  

Charter  Oak  mine  _ 

Wheal  Rose  mine  

Iron  Mask  mine  . 

Bannack  mining  district  

Bannack  Gold  Mining  and  Milling  Company 

Excelsior  mine  

Golden  Leaf  group  

Blue  Grass  and  Gold  Bug  mines  

Hendricks  mine  

Placer  deposits  * ’ 

The  Argenta  area  

General  geology  

Character  and  distribution  of  the  rocks 

Algonkian  system  

S'pokane  formation  

Cambrian  system  

Flathead  formation  

Tilden  formation  

Devonian  system  

Ermont  formation  

Carboniferous  system  

Mississippian  series  

Pennsylvanian  series  

Tertiary  gravels  

Quaternary  deposits  

Glacial  moraine  

Intrusive  igneous  rocks  

General  features  

Quartz  monzonite  

Petrography  

Granodorite  

Petrography  

Andesite  porphyry  

Petrography  

Dacite  porphyry  

Petrography  

Rhyolite  porphyry  

Contact  metamorphic  effects  

Extrusive  igneous  rocks  

Rhyolite  porphyry  

Trachyte  porphyry  

Deformation  

General  features  

Principal  folds  and  faults  

Ore  deposits  

Historical  sketch  of  mining  

Classification  of  the  ore  deposits  

Pipe-like  ore  bodies  in  limestone  

Tuscarora  Mining  and  Smelting  Co.  property  

Tabular  ore  shoots  along  bedding  planes  in  limestone 

Legal  Tender  mine  ; 

Spanish  mine  

Tabular  ore  shoots  along  fissures  in  liestone  

Brownell  mine  

Mauldin  mine  


Pa  r 


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5 

5 

5 

5 

5 

6 
6 
6 
6 
6 
6 


CONTENTS 


5 


The  Argenta  area  (continued) 

Page 

Anaconda  mine  66 

Coolidge  mine  66 

Goldsmith  mine  67 

Contact  deposits  in  limestone  67 

Iron  Mountain  mine  68 

Ermont  mine  69 

Argenta  Mining  Co.  property  70 

Deposits  along  fissures  and  shear  zones  in  quartzite  70 

Carbonate  mine  71 

Groundhog  mine  71 

Deposits  along  fissures  in  shale  71 

Golden  Era  mine  72 

Rena  mine  72 

Midnight  mine  73 

Goldfinch  mine  73 

Dexter  mine  74 

Gladstone  mine  75 

Ore  shoots  along  veins  and  shear  zones  in  quartz  monzonite....  75 

Ferdinand  mine  75 

Jack  Rabbit  mine  76 

Copper  Beli  mine  77 

Bella  mine  77 


ILLUSTRATIONS 

Plate  Page 

I.  Topographic  and  geologic  map  of  the  Bannack  district In  pocket 

II.  Topographic  and  geologic  map  of  the  Argenta  district In  pocket 

III.  A.  Bannack,  Montana,  looking  northeast  14 

B.  Tilted  Flathead  quartzite  east  of  French  Creek  14 

IV.  A.  Intrusive  contact  of  granodiorite  with  Madison  limestone  15 

B.  Adjustment  of  Grasshopper  Creek  to  the  tilted  “Red  Beds” 15 

V.  Photomicrographs  of  granodiorite  from  the  Bannack  district  20 

VI.  Photomicrographs  of  extrusive  rocks  from  the  Bannack  district 24 

VII.  A.  Madison  limestone  overlying  folded  “Red  Beds”  26 

B.  Minor  folding  developed  along  fault  26 

VIII.  Map  of  the  Blue  Wing  workings  of  Kent  mine  32 

IX.  Photomicrographs  of  ores  from  the  Kent  and  Del  Monte  mines  34 

X.  Photomicrographs  of  ores  from  the  Bannack  district  42 

XI.  A.  Glacial  moraine  at  the  mouth  of  Rattlesnake  Creek  canyon 46 

B.  Steeply  inclined  limestone  beds  46 

XII.  1.  Ripple  marks  in  Spokane  formation  47 

2.  Mud  cracks  from  near  the  top  of  the  Spokane  formation  47 

3.  Oolitic  limestone  from  near  the  top  of  the  Tilden  formation  47 

4.  Black  magnesian  limestone  from  base  of  Ermont  formation  47 

XIII.  Photomicrographs  of  intrusive  rocks  from  the  Argenta  district  54 

XIV.  Map  of  the  Tuscarora  and  Gov.  Tilden  mines  60 

Figure 

1.  Index  map  of  Montana  showing  Bannack  and  Argenta  10 

2.  Map  showing  intrusive  relations  on  Wallace  level  of  Wadams  mine  41 


PREFACE 


Bannack  and  Argenta  are  part  of  the  Old  West.  Bannack  was 
the  first  placer  camp  of  significance  in  Montana  and  the  scene  of 
the  first  successful  gold  dredging  operations  in  America,  whereas 
it  was  at  Argenta  that  the  first  successful  lead-silver  mining  and 
smelting  operations  in  Montana  were  begun.  At  Bannack  the  wave 
of  civilization  sweeping  eastward  from  the  Pacific  met  the  west- 
ward advancing  wave  from  the  Atlantic.  It  was  here  that  the  gap 
between  the  two  frontiers  was  closed  and  that  “forty-niners”  from 
California  taught  men  from  the  “states”  to  use  the  pan,  the  rocker, 
and  the  sluice-box. 

But  the  history  of  the  past  is  only  an  incidental  feature  of  this 
publication.  The  prime  purpose  is  to  illustrate  the  application  of 
the  new  geology  to  the  old  camps  in  the  hope  that  by  careful  scien- 
tific analysis  of  the  causes  which  have  led  to  the  formation  of  the 
bonanzas  of  the  past,  stimulus  may  be  given  to  the  revival  of  pro- 
ductive activity  in  the  future. 

Bannack  and  Argenta  are  typical  of  the  numerous  and  more 
or  less  deserted  mining  camps  which  are  dotted  as  a group  of  satel- 
lites about  the  Boulder  batholith  and  from  which,  in  the  aggregate, 
several  hundred  million  dollars  in  gold  and  silver  have  been  pro- 
duced. A mine  is  a wasting  asset,  and  it  is  doubtless  true  that  cer- 
tain of  the  richly  productive  ore-bodies  of  the  Boulder  batholith 
have  been  exhausted.  On  the  other  hand,  it  is  doubtless  equally 
true  that  certain  mines  of  the  past  were  abandoned  either  because 
of  failure  to  understand  the  genesis  and  structure  of  the  ore-bodies, 
or  because  of  inability  to  deal  successfully  with  the  refractory  and 
complex  ores  by  the  metallurgy  then  current. 

To  the  solution  of  the  problems — geological  and  metallurgical — 
presented  by  these  formerly  productive  areas,  the  Bureau  hopes  to 
make  a substantial  contribution  through  such  studies  as  are  typi- 
fied by  this  publication,  “The  Geology  and  Ore  Deposits  of  Bannack 
and  Argenta.”  It  has  been  the  endeavor  throughout  the  prepara- 
tion of  this  report  to  make  it  easily  understood  by  the  intelligent 
miner,  prospector,  and  layman;  but  at  the  same  time  to  include 
the  essential  basic  scientific  facts  needed  by  the  trained  geologist 
or  engineer  in  order  that  he  may  make  an  intelligent  detailed  ex- 
amination of  a specific  property,  for  without  a favorable  report 
from  a competent  engineer  there  is  no  hope  of  interesting  capital 
in  mining  development. 


Francis  A.  Thomson,  Director. 


THE  GEOLOGY  AND  ORE  DEPOSITS  OF 
BANNACK  AND  ARGENTA,  MONTANA 


By  Philip  J.  Shenon 


SUMMARY 

The  areas  described  in  this  report  include  30  square  miles  near 
Bannack  and  20  square  miles  in  the  immediate  vicinity  of  Argenta, 
Montana.  The  Argenta  area  lies  5 miles  northeast  of  the  Bannack 
area. 

These  two  districts  include  the  first  important  placer  and  lode 
mines  in  Montana,  and  many  of  them  have  been  worked  intermit- 
tently up  to  the  present  time.  The  mines  have  produced  gold, 
silver,  lead,  zinc,  and  copper  in  considerable  quantity.  The*  total 
production  of  the  Bannack  area  is  estimated  at  $12,000,000  and 
that  of  the  Argenta  area  at  $1,500,000. 

The  oldest  known  rocks  of  sedimentary  origin  exposed  in  the 
Bannack  district  are  limestones  of  Mississippian  age.  The  youngest 
stratified  rocks  exposed  in  the  vicinity  are  “Red  Beds”  of  probably 
Triassic  age.  Consolidated  sedimentary  rocks  ranging  in  age  from 
pre-Cambrian  to  Pennsylvanian  are  found  in  the  Argenta  area.  They 
include  thick  deposits  of  limestones,  quartzites,  and  shales.  The  un- 
consolidated materials  include  terrace  gravels  and  glacial  moraine. 
Because  of  their  positions  the  terrace  gravels  have  been  classified 
into  “Upper  Bench  Gravels”  and  “Lower  Bench  Gravels”. 

Former  igneous  activity  manifests  itself  in  both  areas  as  flows, 
tuffs  and  intrusives.  The  ore  deposits  are  closely  related  to  intru- 
sive rocks  of  intermediate  composition. 

All  of  the  consolidated  rocks  have  been  folded  and  displaced 
by  overthrust  faulting.  Normal  faults  have  caused  displacements 
on  a smaller  scale. 

Valuable  ore  deposits  occur  in  both  sedimentary  and  intrusive 
rocks  but  are  everywhere  located  at  or  near  the  intrusive  contacts. 
Most  of  the  deposits  were  small  or  moderate  in  size  but  practically 
all  were  high  grade.  The  deposits  with  obvious  exposures  have  been 
largely  exhausted  but  it  is  altogether  possible  that  additional  dis- 
coveries may  be  made. 


INTRODUCTION 

PURPOSE  AND  SCOPE  OF  THE  REPORT 

The  first  part  of  the  field  work  for  the  Bannack  report  was 
done  during  the  summer  months  of  1925.  Another  month  was  spent 
at  geological  investigation  in  1928.  The  field  work  for  the  Argenta 
report  covered  a period  of  nearly  two  months  during  the  summer 
of  1929. 

The  report  on  the  Bannack  area  was  first  assembled  at  the 
University  of  Minnesota1  during  the  winter  and  spring  of  1925-26 
and,  except  for  condensation  and  rearrangement  and  the  added 
description  of  the  Hendricks  mine,  remains  essentially  as  originally 
written.  The  Argenta  report  was  prepared  during  the  spring  and 
summer  of  1930  at  the  Montana  School  of  Mines. 

Section  corners  served  as  the  principal  horizontal  control  for 
the  construction  of  the  topographic  maps  whereas  the  secondary 
points  were  located  by  Brunton  intersections  and  by  pacing. 
The  plane-table  was  used  for  part  of  the  work  in  the  Bannack  area 
but  all  of  the  elevations  in  the  Argenta  area  were  determined  by 
aneroid  barometer.  The  formation  boundaries  were  followed  out 
and  mapped  and  are  delineated  as  accurately  as  the  topography. 
Broken  lines  are  used  where  the  contacts  are  doubtful. 

Fifty  mines  and  prospects  were  visited  during  the  course  of 
the  work  but  due  to  the  pressure  of  time  only  a few  of  them  were 
mapped.  However,  the  characteristics  of  each  have  been  described 
in  more  or  less  detail. 


A CKNO  WLED  GHENT  S 

It  is  a pleasure  to  acknowledge  the  numerous  courtesies  which 
have  facilitated  the  field  work.  Among  many  others,  Messrs. 
William  Dunn,  C.  H.  Stallings,  Frank  Sinnott  and  F.  L.  Graves  (now 
deceased)  of  Bannack;  George  Metlen,  John  Coppin,  J.  B.  Somers, 
D.  V.  Erwin,  William  Corbett  and  G.  V.  Elder  of  Dillon;  A.  H. 
French,  George  W.  French,  W.  J.  Cushing  and  George  Knapp  of 
Argenta;  and  Alexander  Leggat  and  Samuel  Barker,  Jr.,  of  Butte, 
were  generous  in  giving  time  and  information. 

1.  A report  on  the  geology  of  the  Bannack  district  was  submitted  by  the  writer  to  the  Gradu- 
ate School  of  the  University  of  Minnesota  in  partial  fulfillment  for  the  degree  of  Doctor 
of  Philosophy. 


8 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA 


9 


During  the  preparation  of  the  Bannack  report  the  writer  re- 
ceived assistance  and  many  suggestions  from  the  members  of  the 
Geology  Department  of  the  University  of  Minnesota.  Special  ac- 
knowledgment is  due  Dr.  W.  H.  Emmons  and  Dr.  F.  F.  Grout  for 
helpful  suggestions  and  criticisms.  Mr.  It.  J.  Leonard  identified  the 
fossils  that  served  to  correlate  the  sedimentary  rocks.  Acknowledg- 
ment also  is  due  Dr.  G.  M.  Schwarts  for  assistance  and  advice  ren- 
dered during  the  study  of  the  polished  sections.  Mr.  W.  S.  Yarwood 
made  one  complete  rock  analysis  and  Dr.  R.  J.  Leonard  one  incom- 
plete analysis. 

The  writer  wishes  to  express  his  thanks  to  President  Francis 
A.  Thomson  of  the  Montana  School  of  Mines  for  his  help  and  criti- 
cism throughout  the  preparation  of  the  report.  Thanks  are  also 
due  Dr.  E.  S.  Perry  for  his  criticism  and  for  assistance  in  photog- 
raphy. Mr.  L.  H.  Hart  of  the  Anaconda  Copper  Mining  Company 
was  generous  with  information  and  comments  on  the  geology  of 
the  Tuscarora  and  Governor  Tilden  mines.  Mr.  George  H.  Girty 
of  the  U.  S.  Geological  Survey  identified  the  fossils  from  the  Ar- 
genta  district.  Credit  is  due  Mr.  Romer  H.  Guenther  and  Mr.  S.  F. 
Hornbeck  of  the  Anaconda  Copper  Mining  Company  for  the  draft- 
ing of  the  maps. 


GEOGRAPHY 


SITUATION 

The  Argenta  and  Bannack  areas  (fig.  1)  are  centrally  located 
in  Beaverhead  County,  southwestern  Montana,  and  for  the  most 
part  lie  within  the  Dillon  Quadrangle2.  The  Argenta  area  is  in 
T.  9 S.,  Rs.  11  and  12  E.,  and  comprises  an  area  of  20  square  miles; 
the  Bannack  area  is  in  Tps.  7 and  8 S.,  R.  11  W.,  and  includes  an  area 
of  30  square  miles.  The  Blue  Wing  mining  district  occupies  ap- 
proximately the  northern  half  of  the  Bannack  area  and  the  Bannack 
mining  district  the  southern  half  (PI.  I) . 


FIGURE  1.  INDEX  MAP  OF  MONTANA 
SHOWING  BANNACK  AND  ARGENTA 


Dillon  is  the  nearest  railroad  shipping  point  for  the  Argenta 
and  Blue  Wing  districts  which  lie,  respectively,  14  and  18  miles 
west  of  Dillon.  Ore  from  Bannack  is  shipped  from  Grant,  12  miles 
to  the  west,  on  the  Gilmore  and  Pittsburgh  railroad.  A direct 
water-grade  highway  to  connect  Bannack  with  the  Oregon  Short 
Line  railroad  at  Barratt  Station,  a distance  of  about  14  miles,  is 
under  consideration. 

TOPOGRAPHY 

The  Bannack  and  Argenta  areas  lie  in  a section  of  the  Rocky 
Mountain  province  characterized  by  a series  of  north-south  trend- 
ing mountain  ranges  which  are  separated  by  broad  intermontane 
troughs.  The  main  mountain  masses  are  well  rounded  and  charac- 

2.  Winchell,  A.  N'.,  U.  S.  Geol.  Survey  Bull.  574,  1914. 

10 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA 


11 


terized  by  flat  summit  areas  which  Umpleby3  has  described  as  an 
old  erosion  surface.  The  smooth  mountain  slopes  are,  however, 
dissected  by  steep  V-shaped  valleys  that  have  locally  been  widened 
by  glaciation. 

The  maximum  relief  within  the  mapped  areas  is  approximately 
1800  feet.  The  highest  point  in  the  region,  Robbers’  Roost,  is  lo- 
cated in  the  northern  part  of  the  Bannack  district;  it  attains  an 
altitude  of  7600  feet  (PI.  I)  and  because  of  its  prominence  was 
used  as  a lookout  station  by  the  early-day  road  agents,  and  hence 
the  name.  The  lowest  point  is  just  south  of  the  junction  of 
Spring  Gulch  and  Grasshopper  Creek  at  an  elevation  of  5800  feet. 
The  high  range,  composed  largely  of  tilted  limestones  and  quartz- 
ites, running  north  and  south  through  the  Bannack  and  Argenta 
areas  weathers  into  sharp  cliffs  and  jagged  gulches  in  marked  con- 
trast with  the  more  rounded  topography  developed  in  the  gravels 
to  the  west  and  the  lavas  and  gravels  to  the  east  of  this  central 
highland. 

The  region  described  in  this  report  is  drained  by  Rattlesnake 
and  Grasshopper  Creeks,  both  of  which  flow  into  Beaverhead  River, 
a large  tributary  of  the  Missouri.  Rattlesnake  Creek  has  its  head- 
waters in  a series  of  wide  glaciated  valleys  south  of  Mt.  Torrey. 
Thence  it  flows  southeastward,  partly  through  glacial  debris,  to  a 
point  about  4 miles  from  Argenta,  where  the  creek  leaves  the  nar- 
row V-shaped  valley  to  enter  a wider  valley  through  which  it  travels 
the  remainder  of  its  course  to  Beaverhead  River,  four  miles  south  of 
Dillon.  Near  Argenta,  Rattlesnake  Creek  has  carved  a well-defined 
terrace  into  gravel  beds  deposited  by  an  ancient  drainage  system4. 

Grasshopper  Creek  rises  near  the  base  of  Baldy  Mountain  and 
flows  southward  through  a wide,  alluvial-filled  valley  for  about  20 
miles  and  then,  west  of  Bannack,  turns  almost  at  right  angles  and 
flows  the  remainder  of  its  course  through  a narrow  gorge,  whereas 
the  ancient  gravel-filled  stream  channel  continues  southward  to 
Horse  Prairie  Creek.  According  to  Atwood5,  the  early  Tertiary 
drainage  of  southwestern  Montana  was  to  the  southwest  instead  of 
to  the  northeast  as  it  is  today.  After  the  early  Tertiary  drainage 
was  blocked  by  lava  flows  and  warping,  there  followed  a long  period 
of  deposition  in  the  intermontane  basins  while  the  headwaters  of 
the  Missouri  were  advancing  westward.  By  active  headward  erosion 
the  Missouri  finally  captured  the  drainage  of  southwestern  Mon- 
tana; and  yet,  for  the  most  part,  the  present  drainage,  although 


3.  Umpleby,  J.  B.,  Jour,  of  Geol.,  vol.  20,  pp.  139-147  (1912). 

4.  Atwood,  W.  W.,  Economic  Geology,  vol.  11,  No.  8,  pp.  698-732,  1916. 

5.  Op.  cit. 


12  BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 

reversed  in  direction,  still  follows  the  ancient  stream  valleys.  Im- 
mediately west  of  the  mapped  area,  Grasshopper  Creek  follows  one 
of  these  old  valleys  to  a point  not  far  from  Bannack  where  the 
stream  is  sharply  diverted  eastward  through  a youthful  valley  to 
Beaverhead  River.  The  apparent  entrenchment  meandering  in  the 
NW.14  of  sec.  16  is  due  to  the  adjustment  of  the  stream  to  the 
rock  structures  during  headward  erosion  and  is  entirely  local 
(PI.  IV-B) . 

CLIMATE  AND  VEGETATION 

The  climate  is  semi-arid,  the  annual  precipitation  ranging  from 
15  to  20  inches.  The  summers  are  warm  and  pleasant  but  the 
winters  are  usually  cold.  The  mean  average  temperature  is  about 
42  degrees  F.  and  the  extreme  maximum  and  minimum  tempera- 
tures are  about  90  degrees  F.  and  30  degrees  F.,  respectively. 
The  following  tables  give  precipitation  and  snowfall  data  for  Dillon 
but  can  be  considered  as  representative  of  Bannack  and  Argenta6: 

Monthly  and  Annual  Precipitation,  in  Inches,  at  Dillon,  Montana  (1920) 

Jan.  Feb.  Mar.  Apr.  May  June  July  Aug.  Sept.  Oct.  Nov.  Dec.  Annual 

.35  1.40  1.71  1.95  3.41  2.44  2.70  0.91  1.26  0.88  0.51  0.40  17.92 

Monthly  and  Annual  Snowfall,  in  Inches,  at  Dillon,  Montana  (1920) 

Jan.  Feb.  Mar.  Apr.  May  June  July  Aug.  Sept.  Oct.  Nov.  Dec.  Annual 

3.0  8.0  4.1  11.0  Tr.  0.0  0.0  0.0  3.0  2.0  5.0-  3.5  39.6 

Medium-sized  evergreen  trees  are  quite  abundant  although  in 
certain  sections  of  the  area  the  timber  has  been  nearly  depleted. 
The  remaining  timber  is  practically  limited  to  the  highland  area 
extending  north  and  south  through  the  region.  Only  isolated 
patches  of  timber  grow  in  the  areas  occupied  by  the  volcanic  rocks 
and  much  of  the  accessible  timber  in  the  lowlands  has  been  utilized. 
Sufficient  timber  for  extensive  mining  operations  is,  however,  still 
available.  Most  of  the  untimbered  country  is  covered  with  grease- 
wood  and  sagebrush.  Bunch  grass  is  abundant  so  that  the  region 
supports  a considerable  number  of  sheep  and  cattle  during  the 
grazing  season. 


6.  Report  of  the  Chief  of  the  U.  S.  Weather  Bureau  for  1920-21. 


BIBLIOGRAPHY 


The  large  scale  topographic  map  of  the  Dillon  Quadrangle  pre- 
pared by  Frank  Tweedy  in  1887  and  1888  for  the  United  States 
Geological  Survey,  includes  the  Argenta  district  and  the  eastern 
part  of  the  Bannack  area,  as  mapped  by  the  writer.  The  scale  of 
the  map  is  1 to  250,000  or  about  four  miles  to  the  inch,  and  the 
contour  interval  is  200  feet.  The  following  publications  relate  to 
the  geology  and  mining  industry  of  the  Argenta  and  Bannack 
districts : 


1868.  BROWNE,  J.  ROSS,  Mineral  resources  of  the  United  States  for  1866,  Montana,  pp.  498-506. 

1868.  KEYES,  W.  S.,  Mineral  resources  of  the  United  States  for  1866,  Appendix,  pp.  38-56. 

1869-1877.  RAYMOND,  R.  W.,  EATON,  A.  K.,  WHEELER,  W.  F.,  etc.  Mineral  resources  of  the 
region  west  of  the  Rocky  Mountains,  for  1869,  pn.  134-152  ; for  1870,  pp.  204-217  ; for  1871, 
pp.  261-273;  for  1872,  pp . 216-221;  for  1873,  pp . 367-374;  for  1874,  pp . 323-327;  for 
1875,  pp.  237-245. 

1885.  LEESON,  M.  A.,  History  of  Montana,  1739  to  1885,  Chicago,  1885,  1867  pages. 

1885.  EMMONS,  S.  F.,  Geological  sketch  of  the  Rocky  mountain  division : Tenth  Census,  vol. 
13,  pp.  94-100. 

1890.  BANCROFT,  H.  H.,  History  of  Washington,  Idaho,  and  Montana,  1848  to  1889,  San  Fran- 
cisco, 1890,  pp.  589-808,  particularly  pp.  620-627,  and  pp.  721-728. 

1897.  BARREL,  R.  W.,  The  mineral  formation  of  the  Golden  Leaf  mines  (Beaverhead  County, 
Montana)  : Eng.  and  Min.  Jour.,  vol.  64,  p.  64. 

1903.  WEED,  W.  H.,  Ore  deposits  near  igneous  contacts  : Trans.  A.  I.  M.  E.,  vol.  33,  p.  732. 

1905.  DOUGLAS,  E.,  Some  notes  on  the  geology  of  southwestern  Montana : Carnegie  Museum 
Memoir  3,  pp.  407-428. 

1914.  WINCHELL,  A.  N.,  Mining  districts  of  the  Dillon  Quadrangle,  Montana  and  adjacent  areas: 
U.  S.  Geol.  Sur.  Bull.  574. 

1915.  BILLINGSLEY,  PAUL:  The  Boulder  Batholith  of  Montana:  Trans.  A.  I.  M.  M.,  vol.  51,  pp. 
31-56. 

1915.  NOYES,  A.  J.,  Dinsdale’s  Vigilantes  of  Montana,  Montana  State  Publishing  Co.,  Helena, 
Montana. 

1916.  ATWOOD,  W.  W.,  The  physiographic  conditions  at  Butte,  Montana  and  Bingham  Canyon, 
Utah,  when  the  copper  ores  in  these  districts  were  enriched:  Econ.  Geol.  vol.  11,  No.  8, 
pp.  697-740. 

1916.  BILLINGSLEY,  PAUL,  and  GRIMES,  J.  A.,  Ore  deposits  of  the  Boulder  Batholith  of  Mon- 
tana: Trans.  A.  I.  M.  E.,  vol.  58,  pp.  284-361. 

1916.  JENNINGS,  HENNEN,  The  history  and  development  of  gold  dredging  in  Montana:  U.  S 
Bureau  of  Mines  Bull.  121. 

1927.  SHENON,  P.  J.,  Gold  at  Bannack,  Montana:  Eng.  and  Min.  Jour.,  vol.  123,  p.  326. 

1930.  FRENCH,  G.  W.,  Argenta,  first  lead-silver  camp  in  Montana,  still  shipping  ore:  Mining 
Truth,  Spokane,  Wash.,  April  3,  1930,  p.  23. 


13 


THE  BANNACK  AREA 
GENERAL  GEOLOGY 

CHARACTER  AND  DISTRIBUTION  OF  THE  ROCKS 

The  prevailing  rocks  of  the  region  are  igneous  and  are  most 
abundant  in  the  eastern  half  of  the  area.  They  include  granodiorite, 
andesite,  dacite,  rhyolite  and  basalt.  Of  these  the  extrusive  rocks 
greatly  predominate. 

The  sedimentary  section  in  the  Bannack  district  is  far  from 
complete,  although  over  2000  feet  of  sediments  are  included,  rang- 
ing in  age  from  Lower  Mississippian  to  unconsolidated  Quaternary 
gravels.  Limestones  of  Mississippian  age  are  widespread,  but  Juras- 
sic and  Cretaceous  sediments  were  not  observed.  Erosion  has  re- 
moved the  consolidated  post-Carboniferous  sedimentary  rocks  ex- 
cept where  they  have  been  protected  by  overthrust  faulting.  The 
distribution  of  the  rocks  is  shown  on  the  geologic  map  forming 
Plate  I. 

CARBONIFEROUS  SYSTEM 

MADISON  FORMATION 

The  Madison  formation,  consisting  mainly  of  grayish-blue  lime- 
stone, is  very  well  developed  in  the  Bannack  region  where  it  attains 
a thickness  of  about  1200  feet.  Although  the  base  of  this  formation 
was  not  definitely  fixed,  fossil  evidence  indicates  the  presence  of 
the  basal  beds.  Some  grayish-green  and  maroon-colored  shales, 
immediately  west  of  the  fault  in  the  SE.14  of  sec.  8,  were  tentatively 
mapped  with  the  Madison  although  no  fossils  to  fix  their  age  were 
found. 

About  200  feet  of  the  lowest  exposure  of  the  Madison  forma- 
tion is  comprised  of  alternating  grayish-blue,  bluish-white,  and 
pinkish  crystalline  limestone.  Above  this  comes  about  200  feet  of 
bluish-gray  limestone  with  abundant  organic  remains.  Then  fol- 
lows about  150  feet  of  dark  grayish-blue  limestone  with  numerous 
lenses  and  nodules  of  grayish-black  and  black  chert.  This  is  fol- 
lowed by  about  400  feet  of  massive  grayish-blue  limestone,  while 
nearer  the  top  the  formation  becomes  predominantly  red  in  color 
and  the  rocks  are  more  arenaceous.  A peculiar  grayish-blue  con- 
glomerate composed  of  limestone  fragments  was  noted  near  the 
top  of  the  formation.  It  is  exposed  on  the  high  point  in  the  W.1/^ 
sec.  17.  Although  the  red  arenaceous  limestones  were  mapped  with 
the  Madison  formation  it  is  quite  possible  that  they  correspond  with 

7.  Peale,  A.  C.,  U.  S.  Geol.  Survey  Folio  24,  p.  2,  1896. 

14 


MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


Bulletin  6,  Plate  III 


A.  BANNACK,  MONTANA,  LOOKING  NORTHEAST.  TERTIARY  GRAVELS  IN  LEFT 
BACKGROUND  AND  TILTED  LIMESTONE  IN  RIGHT  BACKGROUND. 


B.  TILTED  FLATHEAD  QUARTZITE  (center)  JUST  EAST  OF  FRENCH  CREEK, 
ARGENTA  DISTRICT.  THE  QUARTZITE  BORDERS  SPOKANE  SHALE 
WHICH  OCCUPIES  THE  CENTER  OF  A BROAD  ANTICLINAL  FOLD. 


MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


Bulletin  6,  Plate  IY 


A.  INTRUSIVE  CONTACT  OF  GRANODIORITE  WITH  MADISON  LIMESTONE 
JUST  EAST  OF  BANNACK.  NOTE  APOPHYSIS  OF  INTRUSIVE 
EXTENDING  INTO  LIMESTONE  IN  LEFT  FOREGROUND. 


B.  ADJUSTMENT  OF  GRASSHOPPER  CREEK  TO  THE  TILTED 
“RED  BEDS”  IN  THE  N.W.%  OF  SEC.  16 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA 


15 


north  of  Mann  Gulch  where  it  occupies  two  synclinal  troughs, 
the  “red”  limestones  of  the  Three  Forks  area7  where  they  are  in- 
cluded with  the  Quadrant  formation.  Fossils  from  the  Argenta  dis- 
trict identified  by  G.  W.  Girty  of  the  U.  S.  Geological  Survey,  in- 
dicate that  limestones  of  both  Brazer  (upper  Mississippian)  and 
Wells  (Pennsylvanian)  age  are  present  in  that  district,  and  a more 
complete  fossil  collection  from  the  Bannack  region  will,  no  doubt, 
prove  the  same  thing  to  be  true  in  that  area.  The  fossils  collected 
from  the  Madison  formation  were  identified  by  Dr.  R.  J.  Leonard 
and  are  listed  below: 


The  Quadrant,  which  overlies  the  Madison  formation,  is  ex- 
posed mainly  in  the  extreme  northern  and  southern  ends  of  the 
area.  It  consists  predominantly  of  quartzite  which  grades  upward 
into  a fine-grained  sandstone.  Talus  developed  on  the  steep  slopes 
by  the  weathering  of  these  rocks  usually  conceals  the  contacts 
with  the  other  formations.  The  top  of  the  formation  has  been  re- 
moved by  erosion  but  the  base  is  well  exposed  in  the  saddle  just 
south  of  Bannack  Point  where  it  rests  upon  a bed  of  woody-appear- 
ing  shale  about  two  feet  in  thickness.  Beneath  this  woody-appear- 
ing  shale  is  a thin  layer  of  black  organic  shale,  less  than  an  inch 
in  thickness,  which  in  turn  rests  upon  a massive  blue  limestone. 
Beneath  this  blue  limestone  are  the  red  and  pink  arenaceous  lime- 
stones. The  vitreous  quartzite  which  comprises  the  lower  part  of 
the  Quadrant  formation  is  white  or  pinkish-white  in  color  but 
weathers  to  reddish-brown  on  exposed  surfaces.  Bedding  was  not 
recognized.  Because  of  the  intense  fracturing  and  jointing  the 
quartzite  has  a hackly  appearance.  Microscopic  examination  proved 
this  to  be  an  unusually  pure  quartzite  composed  largely  of  rounded 
quartz  grains,  showing  marked  secondary  growth,  with  some  in- 
terstitial silica  and  a few  isolated  grains  of  biotite.  The  quartz 
grains  are  uniform  in  size  and  average  about  0.15  mm.  in  diameter. 
The  thickest  section  of  the  Quadrant  formation  is  exposed  just 


Amplexus  sp. 
Camarotechia  metallica 
Camarotechia  sp. 
Cleiothyris  roissyi 
Crania  laevis 
Crino.d  stem  fragments 
Cyathophyllum  sp. 
Derbya  crassa? 

Eumetria  marcyi 
Fenestella  sp. 
Murchisonia  sp. 
Nodosinella 
Orthotetes  inflatus  ? 
Pleurophorus  sp. 
Productella  concentrica  ? 


Productus  arcuatus 
Productus  cora 
Productus  laevicostus 
Productus  semireticulatus 
Rhombopora  sp. 

Schizophoria  swallovi 
Spirifer  centronatus 
Spirifer  (Delthyris)  cf.  tullius 
Spiriferina  cristata 
Spirifer  rockymontanus 
Straparollus  luxus  ? 
Straparollus  cf.  similis 
Syringopora  sp. 

Zaphrentis  excentrica 
Zaphrentis  stansburyi 


QUADRANT  FORMATION 


16 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


The  synclinal  trough  occupied  by  Robbers’  Roost,  the  highest  point, 
in  the  region,  includes  a section  over  500  feet  in  thickness. 

The  age  of  the  formation  correlated  with  the  Quadrant  is  prob- 
ably Pennsylvanian.  Calkins8  obtained  Pennsylvanian  fossils  from 
the  Quadrant  formations  in  the  Philipsburg  quadrangle  and  Girty9 
regards  the  fossils  found  in  the  Quadrant  formation  of  the  Snow- 
crest  mountains,  southwest  of  Virginia  City,  as  of  early  Pennsyl- 
vanian age.  No  fossils  were  obtained  from  this  formation  in  the 
Bannack  district,  but  those  found  in  the  red  arenaceous  limestones 
beneath  it  were  identified  as  upper  Madison.  Fossils  of  probable 
Wells  (Pennsylvanian)  age  were  found  in  limestone  beds  beneath 
the  quadrant  quartzite  in  the  Argenta  district. 

MESOZOIC  SYSTEM 

“RED  BEDS” 

The  “Red  Beds”  are  exposed  for  the  most  part  in  the  southern 
end  of  the  area,  disconformably  underlying  Madison  limestones. 
Their  preservation  is  due  largely  to  the  fact  that  the  overthrust 
Madison  limestones  have  protected  them  from  erosion. 

The  “Red  Beds”  consist  largely  of  alternating  beds  of  red  con- 
glomerate and  sandstone  with  some  beds  of  grayish-blue  conglom- 
erate. The  beds  are  persistent  and  range  in  thickness  from  about 
1 to  20  feet.  The  pebbles  in  the  conglomerates  vary  considerably 
in  composition,  size,  and  angularity.  Although  blue  limestone- 
pebbles  often  containing  organic  remains  typical  of  Madison  lime- 
stone predominate,  brown  and  white  quartzite,  pink,  buff,  and  black 
chert,  brown  sandstone  and  white  quartz  pebbles  are  common.  The 
largest  pebbles  observed  were  less  than  a foot  in  diameter,  but  the 
average  size  is  probably  less  than  an  inch.  The  quartzite,  sand- 
stone, quartz,  and  chert  pebbles  are  usually  well  rounded,  whereas 
those  of  blue  limestone  are  frequently  angular.  Both  sandstone  and 
conglomerate  are  well  cemented,  the  latter  usually  with  a brownish- 
red  to  brick-red  sandy  material.  Several  beds  of  volcanic  rocks, 
purplish  to  pinkish  in  color,  are  present  in  the  lowest  exposed  por- 
tions of  the  “Red  Beds”.  They  are  in  well  defined  beds  and  are 
clearly  members  of  the  strata  that  comprise  the  “Red  Beds”.  The 
microscope  shows  these  rocks  to  be  made  up  largely  of  volcanic 
glass,  some  with  marked  flow  structures  (PI.  VI,  3) . Although 
these  rocks  are  greatly  altered,  several  feldspars  showing  carls- 
bad  twinning  could  be  seen  and  one  with  albite  twinning  showed 


8.  Emmons,  W.  H.,  and  Calkins,  F.  C. : U.  S.  Geol.  Sur.  Prof.  Paper  78,  pp.  70-74,  1913. 

9.  Condit,  D.  Dale : U.  S.  Geol.  Sur.  Prof.  Paper  120,  p.  116,  1919. 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA 


17 


an  extinction  angle  of  10  degrees.  As  quartz  was  observed,  the 
rocks  are  probably  trachyte  or  latite,  porphyry  and  tuff. 

Neither  the  top  nor  the  bottom  of  the  “Red  Beds”  are  exposed. 
Erosion  has  removed  the  upper  members  while  the  lower  beds  are 
in  fault-contact  with  the  Madison  limestone.  The  thickness  from 
the  contact  with  the  Madison  limestone  to  the  exposed  top  on  the 
south  side  of  Grasshopper  Creek  was  measured  roughly  and  ap- 
proximates 700  to  800  feet.  Cross  sections  indicate  a thickness  of 
at  least  1500  feet. 

No  fossils  were  found  in  the  “Red  Beds”  except  those  included 
in  Madison  pebbles.  They  probably  correspond,  however,  with  the 
Chugwater  formation  (Permian  and  Triassic)  of  southwestern 
Montana10  and  Wyoming11  and,  to  the  north,  of  the  Pryor  Moun- 
tains near  Billings,  Montana12. 

TERTIARY  GRAVELS 

The  extreme  western  part  of  the  region  is  occupied  by  Tertiary 
gravels,  and  terrace  gravels  are  found  above  Grasshopper  Creek 
in  several  places  (plate  I). 

The  predominating  rock  is  red  quartzite,  but  light-colored 
quartzite  comes  next  in  order.  The  pebbles  are  well  rounded  and 
although  usually  about  two  inches  in  diameter,  they  vary  from 
less  than  an  inch  to  about  a foot.  Lesser  amounts  of  angular  lime- 
stone fragments,  as  large  as  three  feet  in  diameter,  and  some  sand- 
stone and  lava  pebbles  are  present  as  are  a few  rounded  pebbles  of 
magnetite.  The  gravel  is  cemented  with  coarse  sandy  material  and 
is  quite  well  indurated. 

The  gravels  are  later  than  the  volcanic  rocks  of  Tertiary  age 
and  antedate  the  advent  of  stream  piracy  in  the  region.  According 
at  Atwood13  the  closed  drainage  of  southwestern  Montana  was 
opened  by  stream  piracy  during  middle  Pliocene. 

AURIFEROUS  GRAVELS 

Most  of  the  auriferous  placer  gravels  are  in  the  present  stream 
channel,  although  some  of  the  older  “bench  gravels”  were  also 
mined  for  their  gold  content.  The  stream  gravels  include  pebbles  of 
all  the  rock  formations  of  the  region  as  well  as  some  not  found  in 
the  vicinity  but  red  quartzite  pebbles  predominate. 

10.  Condit,  D.  Dale,  op.  cit.  p.  119. 

11.  Darton,  N.  H„  U.  S.  Geol.  Sur.  Prof.  Paper  40,  p.  140,  1906. 

12.  Kemp.  J.  F.  and  Billingsley,  Paul,  Bull.  Geol.  Soc.  America,  vol.  32,  p.  466,  1921. 

13.  Atwood,  W.  W.,  op.  cit.  p.  706. 


i.8 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


INTRUSIVE  IGNEOUS  ROCKS 

GRANODIORITE 

Granodiorite,  the  characteristic  intrusive  rock  of  the  Bannack 
area,  is  exposed  in  both  the  Bannack  and  Blue  Wing  mining  districs. 
In  all,  the  exposures  aggregate  less  than  two  square  miles.  These 
small  outcrops  are  probably  isolated  exposures  of  the  main  Boulder 
batholith14. 

The  Boulder  batholith15  is  exposed  over  an  area  of  1100  square 
miles  in  the  mountainous  region  of  western  Montana.  This  batho- 
lith is  probably  a satellite  of  the  Idaho  batholith  which  is  situated 
150  miles  to  the  west  and  covers  and  area  of  20,000  square  miles16. 
Between  the  two  are  many  smaller  exposures  of  intrusive  rocks. 
Field  work  indicates  a genetic  relationship  between  the  isolated  ex- 
posures of  granitic  rocks  in  Montana  so  that  Billingsley17  has  en- 
larged the  term  “Boulder  Batholith”  to  include  the  outlying  tracts. 

The  prevailing  rock  of  the  Bannack  district  is  a fine-grained, 
medium-to-dark-colored  granodiorite.  It  is  more  basic  and  notice- 
ably finer  than  the  prevailing  rocks  of  the  greater  portion  of  the 
Boulder  batholith18  and  quartz  is  not  readily  discernable  in  the 
hand  speeiman. 

In  the  Bannack  mining  district  there  are  three  distinct  out- 
crops of  the  granodiorite  but  in  the  Blue  Wing  mining  district,  with 
the  exception  of  several  small  exposures,  it  occurs  as  a continuous 
mass.  Although  a number  of  apophyses  extend  out  into  limestone, 
the  exposures  are  more  or  less  elliptical  in  outline. 

The  intrusive  nature  of  the  granodiorite  is  made  evident  by  the 
marked  contact  metamorphism  in  the  sediments  about  the  edges, 
by  the  projection  of  apophyses  into  the  sedimentary  rocks,  and  by 
the  manner  in  which  the  granodiorite  truncates  the  upturned  beds 
of  Madison  limestone.  Garnetization  is  common  along  the  contact 
between  the  granodiorite  and  the  limestone  in  the  Blue  Wing  dis- 
trict and  extensive  in  the  Bannack  vicinity.  Apophyses  of  grano- 
diorite can  be  observed  extending  into  the  limestone  in  the  Barton 
drift  at  the  Kent  mine  and  in  a prospect  hole  just  northwest  of  the 
Del  Monte  shaft.  Some  of  the  important  ore  deposits  at  Bannack 
occur  along  apophyses  that  cut  across  bedded  limestone ; the  Excel- 
sior mine  furnishes  a splendid  example. 

The  upper  surface  of  the  intrusive  masses  are  rudely  dome- 

14.  Billingsley,  Paul,  Trans.  A.  I.  M.  E.,  vol.  51,  pp.  31-56,  1915. 

Winchell,  N.  H. : U.  S.  Geol.  Sur.  Bull.  574,  p.  55,  1914. 

15.  Weed,  H.  W.,  U.  S.  Geol.  Sur.  Butte  Special  Folio,  1897. 

16.  Umpleby,  J.  B.,  Jour,  of  Geology,  vol.  20,  p.  145,  1912. 

17.  Billingsley,  Paul,  op.  cit. 

18.  Weed,  W.  H.,  op.  cit. ; Knopf,  Adolph,  op.  cit. 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA 


19 


like  but  they  cut  across  the  bedding  and  are  not  laccoliths  in  the 
strict  sense  of  the  term.  The  outcrops  lack  the  more  rugged  fea- 
tures developed  in  the  tilted  limestone  and  are  eroded  into  well 
rounded  topographic  forms  (PI.  IV.  1).  The  rock  is  traversed  by 
pronounced  systems  of  closely  spaced  joints  and  tends  to  break 
into  small  rhomboidal-shaped  blocks  upon  weathering.  Because  of 
this  pronounced  jointing  the  granodiorite  has  no  economic  value 
as  a building  stone. 

In  the  Bannack  mining  district  all  the  contacts  are  sharp  and 
boundaries  were  easily  mapped,  but  in  the  Blue  Wing  mining  dis- 
trict the  intrusive  rocks  are  in  contact,  on  the  east,  with  an  altered 
grayish-green  rock  of  slightly  porphyritic  or  fine  texture  which 
closely  resembles  the  granodiorite,  and,  as  a result,  considerable 
difficulty  was  experienced  in  mapping.  Microscopic  study  proved 
this  green  porphyry  to  be  an  altered  phase  of  a volcanic  rock. 

PETROGRAPHY 

The  granodiorite  is  prevailingly  fine-grained  and  grayish  to 
grayish-green  in  color.  Feldspars  constitute  about  75  per  cent  of 
the  rock  and  biotite,  hornblende  and  magnetite  make  up  the  greater 
part  of  the  remainder.  Quartz  is  not  readily  discernible  in  the 
hand  specimens.  Pyrite  commonly  occurs  along  joint  planes. 

In  thin  sections  the  microscope  shows  the  bulk  of  the  rock  to 
be  made  up  of  lath-shaped  plagioclase  feldspars,  usually  striated 
which  show  very  marked  zoning  and  usually,  reaction  rims  (PL  V) . 
The  extinction  angles  on  the  twinned  plagioclase  indicates  a com- 
position of  Ab63  An37,  whereas  the  composition  calculated  from  the 
norm  is  Ab58  An42.  The  andesine  crystals  vary  in  size  from  about 
0.03x0.05  millimeters  to  0.28x0.70  millimeters  and  average  about 
0.14x0.20  millimeters.  Optically  abnormal  orthoclase  is  present 
largely  as  interstitial  material  but  generally  constitutes  about  15 
per  cent  of  the  rock.  The  feldspars  are  usually  fresh  but  occasion- 
ally have  a dusty  appearance.  The  central  zones  of  the  plagioclase 
show  the  most  alteration,  largely  to  sericite  and  kaolin.  Smal* 
amounts  of  interstitial  quartz  are  present,  generally  less  than  15 
per  cent.  Biotite  is  the  commonest  dark  constituent  and  makes  up 
about  10  per  cent  of  the  rock.  It  frequently  shows  alteration  to 
chlorite.  The  biotite  often  includes  magnetite,  plagioclase  and  zir- 
con poi kil itically , the  zircon  showing  pleochroic  haloes.  Green  horn- 
blende is  usually  present  in  amounts  ranging  from  5 to  10  per  cent. 
Sometimes  brown  biotite  takes  the  place  of  hornblende,  especially 
around  the  borders.  The  hornblende  is  usually  somewhat  altered 


20 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


to  chlorite,  epidote,  limonite  and  calcite.  Augite  is  generally  present 
in  small  amounts.  Magnetite,  apatite,  zircon,  and  titanite  occur 
as  accessory  minerals.  Magetite  grains,  commonly  square  in  out- 
line, are  disseminated  through  the  sections  but  are  most  abundant 
in  or  near  the  ferromagnesian  minerals.  Magnetite  usually  com- 
prises from  1 to  5 per  cent  of  the  rock  but  apatite,  zircon,  and  titan- 
ite generally  make  up  less  than  1 per  cent. 

A complete  chemical  analysis  of  the  Bannack  intrusive  and  a 
partial  analysis  of  a contact  phase  are  given  below.  Analysis  of 
rocks  from  the  Elkhorn  intrusive  and  from  the  main  Boulder  batho- 
lith  are  included  in  the  table  for  comparison. 


Analysis  of  intrusive  roclcs  from  Bannack  and  adjacent  areas 


1 A B C 2 

SiO. 61.21  60.84  63.87  64.17  46.65 

ALO,  15.20  16.36  15.39  15.25  13.79 

FeoO-i  2.49  2.40  1.93  2.16  10.17 

FeO 3.30  3.23  3.08  2.98 

MgO  4.12  3.85  2.23  2.60  6.75 

CaO  6.05  4.96  4.30  4.24  19.42 

Na,0  3.32  2.90  2.76  2.62 

KO  2.31  4.10  4.18  4.34 

H ,0  92  1.03  .69  .65 

ILO 24  .48  .19  .16 

TiO..  62  .65  .67 


99.78  iOO.15  99.28  99.84  96.78 

1 . Bannack,  Mont.,  W.  S.  Yarwood,  analyst,  Biotite  hornblende  granodiorite. 

A.  Elkhorn  district,  Montana,  E.  C.  Sullivan,  analyst,  Mica  diorite. 

B.  Butte,  Mont.,  Alice  Mine,  W.  F.  Hillebrand,  analyst.  Quartz  monzonite. 

C.  Helena,  Mont.,  Frohner  Mine,  H.  N.  Stokes,  analyst,  Quartz  monzonite. 

2 . Bannack,  Mont.,  R.  J.  Leonard,  analyst.  Contact  phase  of  granodiorite. 

The  normative  mineral  composition  as  calculated  from  the 
chemical  analysis  according  to  the  rules  proposed  by  Cross,  Iddings, 
Pirrson  and  Washington19  may  be  stated  as  follows: 


1 A B C 

Quartz  15.18  11.10  18.84  19.38 

Orthoclase  13.34  24.46  25.02  25.58 

Albite  27.77  24.63  23.06  22.01 

Anorthite  20.02  19.19  17.23  16.96 

Diopside  7.97  4.48  2.72  2.69 

Hypersthene  9.41  11.27  7.57  7.84 

Magnetite  3.71  3.48  2.78  3.25 

Ilmen  ite  1.22  1.22  1.22 


Comparison  of  chemical  analysis  and  normative  calculations 
brings  out  a marked  relationship  between  the  main  Boulder  batho- 
lith  and  the  satellites  exposed  at  Bannack  and  Elkhorn. 

Although  the  intrusive  rock  near  the  contact  is  essentially 
the  same  as  the  central  masses  certain  changes  were  noted.  At 
some  places  along  the  main  contact,  and  particularly  where  blocks 
of  limestone  were  included  in  the  granodiorite,  the  intrusive  rocks 
were  greenish-black  to  almost  black  in  color  or  in  some  cases  of 
a salt  and  pepper  appearance  with  greenish-black  orbicular  segre- 
gations, generally  about  an  inch  in  diameter.  Under  the  microscope 


19.  Washington,  H.  S.,  U.  S.  Geol.  Sur.  Prof.  Paper  99,  1917. 


MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


Bulletin  6,  Plate  V 


3 4- 

PHOTOMICROGRAPHS  OF  GRANODIORITE  FROM  THE 
BANNACK  DISTRICT,  MONTANA. 

1.  Typical  granodiorite  from  the  main  intrusive  south  of  Grasshopper  Creek,  Bannack  mining 
district.  Andesine  feldspar  (a),  biotite  (b),  magnetite  (m),  quartz  (q).  Polarized  light. 
Magnification  45  times. 

2.  Same  showing  zonal  growth  in  andesine  feldspars.  Polarized  light.  Magnification  45  times. 

3.  Typical  granodiorite  from  the  Blue  Wing  mining  district.  Andesine  feldspar  (a),  biotite  (b), 
magnetite  (m),  quartz  (q).  Polarized  light.  Magnification  45  times. 

4.  Granodiorite  from  near  limestone  contact.  Hedenbergite  (h),  andesine  feldspar  (a),  quartz  (q). 
Polarized  light.  Magnification  V 'times. 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA 


21 


these  dark-colored  rocks  were  found  to  be  made  up  largely  of  iron- 
bearing pyroxene  (hedenbergite  70  per  cent,  diopside  30  per  cent) 
with  lesser  amounts  of  plagioclase.  No  biotite  or  hornblende  was 
observed  in  the  thin  sections  studied  (PL  V,  4).  This  type  of  varia- 
tion was  observed  in  the  Golden  Leaf  mine.  However,  here  the  in- 
trusive contained  noticeable  amounts  of  chalcopyrite  and  pyrite.  In 
some  places  on  the  surface  it  was  possible  to  trace  the  gradation 
from  the  hedenbergite  phase  into  a light  green  garnetized  limestone 
which  the  microscope  showed  to  be  made  up  almost  entirely  of 
isotropic  garnet.  The  absence  of  biotite  and  hornblende  and  the 
very  marked  increase  in  hedenbergite  confirms  the  data  of  the 
analysis  which  shows  that  there  was  an  addition  of  lime,  magne- 
sia, and  iron.  The  relationships  of  the  hedenbergite  rock  with 
the  limestone  contacts  and  particularly  with  the  blocks  of  limestone 
included  in  the  intrusive  would  suggest  the  limestone  as  the  source 
of  the  lime  and  possibly  some  magnesia.  The  additional  iron  and 
magnesia  must  have  been  derived  from  the  intrusive  itself  because 
an  analysis  shows  the  white  crystalline  limestone,  some  distance 
from  the  contact,  to  be  very  pure.  The  results  of  the  analysis  of 
the  crystalline  limestone  are  given  below.  This  variation  is  there- 
fore considered  to  be  largely  an  endomorphic  contact  effect. 

* $r: 

• exomoRPhic  Contact  effects 

r - jji  , 

Contact  effects  of  the  gr^bthprite  were  observed  only  in  the 
limestone  so  that  the  alterations  produced  were  quite  similar  from 
place  to  place.  The  most  marked  metamorphism  was  observed  along 
the  apophyses  where  the  contacts  were  exposed  by  mining  opera- 
tions, as  at  the  apex  of  the  arm-like  extension  of  the  granodiorite 
into  the  limestone  at  the  Excelsior  mine. 

A common  effect  observed  was  the  marmarization  of  the  lime- 
stone near  the  contacts  with  the  intrusive  rock.  The  recrystalliza- 
tion may  be  due  in  part  to  movement  because  white  marble  is  at 
places  found  away  from  the  intrusive  contacts.  An  analysis  of  a 
specimen  of  the  white  marble  from  just  west  of  the  Bannack  Gold 
Mining  Company  mill  gave  the  following  analysis : 


CaC03  97.14 

MgC03  1.17 

Impurities  (Fe,  Si09,  Al) 1.12 


99.43 

Garnetization  is  common  near  the  contacts  of  the  intrusive 
with  the  limestones.  At  the  surface  the  garnetized  limestone  has 
a citron  color  but  the  garnets  observed  underground  were  predomin- 


22 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


antly  brownish  or  reddish-brown.  Several  other  minerals  were 
noted  with  the  garnet  but  epidote  is  probably  the  most  common. 

AGE 

The  age  of  the  granodiorite  in  the  Bannack  district  has  not 
been  definitely  fixed.  These  intrusive  rocks  are  known,  however, 
to  be  later  than  the  folding  and  probably  later  than  the  thrust  fault- 
ing. The  “Red  Beds”  are  the  youngest  rocks  of  the  district  known 
with  certainty  to  be  involved  in  the  folding  and  thrust  faulting; 
therefore  the  granodiorite  in  this  region  is  at  least  as  late  as 
Mesozoic. 

Although  Weed20  assigned  a Miocene  age  to  the  Boulder  batho- 
lith,  more  recent  work  indicates  it  to  be  Eocene  or  late  Cretaceous 
in  age.21  Some  of  the  larger  exposures  are  known  to  intrude  rock 
of  Livingston  (late  Cretaceous)  age22  and  the  main  Boulder  batho- 
lith  is  overlain  by  Oligocene  sediments  west  of  Cliff  Mountain23  and 
at  Pipestone  Springs,  near  the  southwest  portion  of  the  mass.24 

Since  it  is  believed  that  the  outlying  granitic  masses  in  west- 
ern Montana  are  isolated  exposures  of  the  main  Boulder  batholith, 
the  granodiorite  at  Bannack  can  be  tentatively  assigned  to  late 
Cretaceous  or  Eocene. 

BASIC  DIKES 

Only  two  dikes  were  noted  cutting  the  limestone.  A grayish- 
black,  fine-grained  dike  with  glassy  borders  cuts  the  garnetized 
limestone  immediately  east  of  the  open  pit  at  the  Gold  Bug  mine. 
It  strikes  N.  50  degrees  E.,  and  dips  60  degrees  N.  Another  dike 
was  noted  in  the  Norman  stope  of  the  Wadams  mine.  It  is  fine- 
grained and  somewhat  lighter  colored  than  the  one  at  the  Gold 
Bug  mine.  It  strikes  N.  40  degrees  E.,  and  dips  70  degrees  S.  The 
microscope  proved  the  specimen  from  the  first  dike  to  be  a basalt. 
The  second  was  not  studied  under  the  microscope. 

EXTRUSIVE  IGNEOUS  ROCKS 

DISTRIBUTION  AND  THICKNESS 

Volcanic  rocks  consisting  of  varieties  of  andesite,  dacite,  rhyo- 
lite, and  basalt  occupy  half  of  the  mapped  area.  The  lavas  extend 
from  the  level  of  Grasshopper  Creek,  at  an  elevation  of  5,800  feet, 
to  an  elevation  of  7,100  feet  on  the  high  point  in  sec.  11,  but  no 

20.  Weed,  W.  H. : U.  S.  Geol.  Sur.  Prof.  Paper  74,  p.  29,  1912. 

21.  Knopf,  Adolph, : U.  S.  Geol.  Sur.  Bull.  527,  p.  34,  1913. 

22.  Emmons,  W.  H.  and  Calkins,  F.  C.  : U.  S.  Geol.  Sur.  Prof.  Paper  78,  p.  83,  1926. 

22.  Stone,  R.  W.  and  Calvert,  W.R.  : Econ.  Geol.  vol.  5,  pp.  551-557,  662-669,  744-764,  1910. 

23.  Douglas,  Earl : Annals  Carnegie  Mus.  Pittsburg,  vol.  5,  pp.  197,  263,  1909. 

24.  Mathew,  W.  D.  : Bull.  Am.  Mus.  Nat.  Hist.  vol.  19,  p.  197,  1903. 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA 


23 


remnants  of  them  were  found  above  that  elevation.  The  relation- 
ship of  the  volcanic  rocks  was  not  studied  in  detail  nor  could  the 
distance  to  which  they  extend  below  the  present  drainage  lines  be 
determined,  but  it  is  certain  that  they  accumulated  to  a great 
thickness. 

ANDESITE 

GENERAL  CHARACTER 

Andesite,  consisting  largely  of  unbroken  flows  but  with  lesser 
amounts  of  breccias  and  tuffs,  is  the  commonest  volcanic  rock  of 
the  Bannack  region.  Although,  when  examined  in  detail,  they 
comprise  a number  of  varieties,  two  types  predominate.  The  com- 
monest variety  is  a grayish-green,  fine-grained  rock  which  usually 
shows  well-developed  flow  banding  and  prominent,  rhombic-shaped, 
white  phenocrysts.  The  other  common  variety  of  andesite  is  a pur- 
plish, fine-grained  rock  with  very  prominent  white  feldspar  pheno- 
crysts commonly  about  1 millimeter  in  length,  showing  striations. 
Greenish  and  purplish  andesite  breccias  occur  in  lesser  amounts. 
Fragments  ranging  in  size  from  5 millimeters  to  3 or  4 centimeters 
Are  abundant  in  these  rocks. 

PETROGRAPHY 

The  green  andesite  contains  phenocrysts  of  feldspar  in  an 
altered,  fine-grained  groundmass.  The  feldspar  phenocrysts  which 
comprise  about  70  per  cent  of  the  rock  are  usually  altered  but  even 
those  showing  the  greatest  change  are  visibly  striated.  Quartz  is 
absent  in  most  of  the  sections.  Residual  patches  of  epidote  and 
calcite,  commonly  including  grains  of  magnetite,  probably  repre- 
sent former  ferromagnesian  phenocrysts.  One  of  the  fresher  speci- 
mens contained  the  following  minerals  in  approximately  the  amounts 
indicated : Andesine  ( Ab6  An4)  60  per  cent,  orthoclase  15  per  cent, 
quartz  1 per  cent,  magnetite  1 per  cent,  titanite  and  apatite  1 per 
cent,  epidote  12  per  cent,  calcite  5 per  cent,  chlorite  and  sericite  5 
per  cent. 

The  purplish  andesite  contains  phenocrysts  of  feldspar,  augite, 
hornblende,  and  small  amounts  of  magnetite  in  a microcrystalline 
groundmass  which  is  stained  a brownish-red  color  with  hematite 
dust.  (See  Fig.  2,  PI.  7).  Although  the  groundmass  is  consider- 
ably altered,  flow-structure  is  apparent.  The  feldspar  phenocrysts 
average  about  1 millimeter  in  length  and  0.5  millimeters  in  width, 
and  comprise  about  50  per  cent  of  the  rock.  A few  rhombic-shaped 
feldspars  with  marked  zoning  occur  here  and  there.  The  plagioclase 
phenocrysts,  which  have  the  composition  of  andesine  (AbG  An4)  are 


24 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


prominently  twinned  according  to  the  albite  and  carlsbad  laws  and 
frequently  contain  numerous  tiny  inclusions.  Orthoclase  comprises 
less  than  5 per  cent  of  the  feldspar.  Phenocrysts  of  light  green 
augite  and  hornblende  with  black  reaction  rims  occur  in  less 
amounts. 

Magnetite,  titanite  and  zircon  occur  as  accessory  minerals,  the 
first  usually  altering  to  limonite  around  the  borders. 

DACITE 

GENERAL  CHARACTER 

Dacite  occurs  in  the  Bannack  district  but  not  as  abundantly 
as  the  andesitic  rocks.  The  most  common  variety  is  a grayish- 
green,  medium  to  fine-grained  porphyritic  rock.  Feldspar,  biotite, 
and  quartz  phenocrysts  can  readily  be  distinguished  with  the  naked 
eye.  Some  breccias  also  apparently  contained  enough  quartz  to  be 
classed  as  dacite  but  were  not  studied  in  thin  section. 

PETROGRAPHY 

Phenocrysts  of  feldspar,  quartz,  biotite,  hornblende  and  magne- 
tite occur  in  a fine-grained  groundmass  (PL  VI,  1).  The  phenocrysts 
comprise  about  65  per  cent  of  the  rock.  Striated  andesine  plagio- 
clase  (An4Ab6),  averaging  about  1 millimeter  in  length  and  0.5 
millimeters  in  width,  comprise  about  65  per  cent  of  the  phenocrysts. 
They  are  somewhat  dusty  in  appearance  due  to  alteration.  The 
rounded  quartz  phenocrysts,  which  are  clear  and  glassy,  show 
corrosion  and  embayment.  Quartz  sometimes  almost  entirely  sur- 
rounds lath-shaped  feldspars  and  poikilitic  inclusions  of  feldspar, 
magnetite  and  biotite  are  common.  The  average  size  of  the  quartz 
phenocrysts  is  about  0.5  millimeters.  Orthoclase  comprises  less 
than  10  per  cent  of  the  phenocrysts.  Biotite  and  hornblende,  con- 
stituting less  than  5 per  cent  of  the  phenocrysts  are  the  predomin- 
ant dark  constituents.  Magnetite,  commonly  showing  alteration  to 
limonite,  is  the  commonest  accessory  mineral.  It  occurs  dissemi- 
nated through  the  groundmass  and  as  square-shaped  crystals  about 
0.2  millimeters  across.  Apatite  and  titanite  occur  also  as  accessory 
minerals.  Calcite  is  abundant  as  a secondary  mineral.  Because  of 
the  abundance  of  quartz  the  rock  is  classified  as  a dacite. 

RHYOLITE 

Rhyolite  is  relatively  rare  in  the  region.  It  is  commonly  frag- 
mental in  structure  and  white  or  pink  in  color.  A pink  breccia  is 
the  most  widespread  (PL  VI,  4).  The  fragments,  contained  in  the 
breccia,  frequently  show  flow  structures,  and  range  in  size  from  1 


MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


Bulletin  6,  Plate  VI 


3 + 


PHOTOMICROGRAPHS  OF  EXTRUSIVE  ROCKS  FROM  THE  BANNACK  DISTRICT. 

1.  Dacite  porphyry  showing  phenocrysts  of  quartz  (q),  biotite  (b),  plagioclase  (p).  Polarized 
light.  Magnification  7 times. 

2.  Andesite  porphyry  showing  plagioclase  phenocrysts  in  a microcrystalline  groundmass.  Polar- 
ized light.  Magnification  7 times. 

3.  Tuff  from  lower  portion  of  “Red  Beds”  showing  glass  shards.  Ordinary  light.  Magnification 
7 times. 

4.  Rhyolite  tuff  showing  fragmental  texture.  Light  colored  mineral  is  quartz.  Darker  fragments 
are  mostly  rock  material.  Polarized  light.  Magnification  7 times. 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA  25 

millimeter  to  several  centimeters.  A white  fine-grained  lava  with 
conspicuous  phenocrysts  of  quartz  and  altered  biotite  occurs  in 
lesser  amounts.  It  contains  small  vesicles  and  solution  cavities.  A 
very  fine-grained  white  rhyolite  tuff  occurs  in  some  abundance. 
It  contains  some  rounded  pebbles  of  foreign  material  and  in  most 
places  is  noticeably  banded. 

BASALT 

Basalt  is  rare.  A few  basaltic  rocks  were  noted  but  because  of 
their  infrequent  occurrence  they  were  not  studied  in  thin  section. 
Winchell25  mentions  the  occurrence  of  a basalt-capped  mesa  about 
5 miles  south  of  Bannack. 

AGE  OF  THE  VOLCANIC  ROCKS 

No  evidence  definitely  fixing  the  age  of  the  volcanic  rocks  was 
found  within  the  region.  It  is  quite  probable  that  there  were  two 
periods  of  volcanic  activity.  The  andesite  rocks  may  have  shared 
in  the  deformation  of  the  region  which,  in  part  at  least,  pre-dated 
the  intrusion  of  the  granodiorite.  The  intense  hydrothermal  alter- 
ation of  the  andesite  suggests  that  they  may  have  been  intruded 
by  the  granodiorite.  These  rocks  may  correspond  in  age  with  the 
andesitic  rocks  in  the  Butte  and  Helena  regions  which  Knopf26  has 
assigned  to  the  late  Cretaceous.  The  basalt  in  the  Bannack  region 
and  to  the  south  is  probably  of  Tertiary  age. 

DEFORMATION 

FOLDING 

Several  major  folds  are  developed  in  the  area  and  minor  fold- 
ing is  pronounced.  Immediately  east  of  Bannack  the  sedimentary 
rocks  have  been  folded  into  a broad  overturned  anticlinal  dome. 
Intrusive  rocks  occupy  the  core  of  this  dome  and  may  have  caused 
the  increase  in  dip  in  their  immediate  vicinity.  A series  of  well- 
developed  folds  occurs  in  the  northern  end  of  the  region.  Quadrant 
quartzite  occupies  the  synclinal  troughs  and  the  older  Madison 
limestones  are  exposed  at  the  crests  of  the  anticlines  (PI.  Ill,  1). 
In  the  vicinity  of  the  Kent  Mine,  about  two  miles  northeast  of 
Bannack,  an  anticlinal  dome  is  exposed  and  its  crest  eroded. 

Minor  folding  is  pronounced  in  the  vicinity  of  thrust  faults, 
especially  on  the  hanging-wall  side  (PI.  VII,  2).  It  is  usually  com- 
plex and  can  only  be  represented  on  the  cross  sections  in  a general 
way. 


25.  Op.  cit.  p.  50. 

26.  Knopf,  Adolph  : op.  cit.,  pp.  23-29. 


26 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


FAULTING 

East  of  Bannack  the  Madison  limestone  can  be  seen  resting 
discordantly  upon  folded  “Red  Beds”.  The  discordance  is  due  to 
overthrust  faulting,  the  fault  having  a general  northerly  strike. 
The  fault  zone  is  present  in  the  Blue  Grass  and  Pioneer  mines27  and 
was  observed  in  the  main  tunnel  of  the  Ingersoll  mine.  This  tunnel 
was  run  its  entire  distance  (150  feet)  in  a white  limestone  gouge. 
In  sec.  9,  an  outlier  of  blue  Madison  limestone  rests  upon  the  “Red 
Beds”  and  contains  abundant  fossils.  It  caps  the  high  point  just 
northwest  of  Bon  Accord.  Considerable  evidence  points  to  the  fact 
that  the  thrusting  was  not  limited  to  one  surface  but  occurred 
along  a number  of  surfaces.  The  fault  exposed  in  secs.  9 and  14  is 
the  best  example  of  this  minor  faulting  (PI.  VII,  2).  Normal  faults 
were  observed  throughout  the  district. 

The  thrust  faulting  at  Bannack  is  of  more  than  local  interest 
because  it  probably  belongs  to  the  great  system  of  overthrusting 
faults  which  extend  at  least  from  Canada  on  the  north,  well  into 
Utah  on  the  south. 

The  Philipsburg  Quadrangle28  north  of  the  Bannack  area,  is 
traversed  from  north  to  south  by  an  overthrust  or  zone  of  over- 
thrusts  bringing  Algonkian  rocks  into  contact  with  Carboniferous 
and  Jurassic  rocks.  Still  farther  north,  the  Lewis  overthrust,  with 
a displacement  of  about  7 miles,  brings  Algonkin  rocks  into  dis- 
cordant contact  with  Cretaceous  rocks.29  The  Bannack  overthrust  in 
Idaho,  south  of  the  Bannack  area,  has  been  described  by  Richards 
and  Mansfield.30  Rocks  from  Cambrian  to  Mississippian  age  have 
been  thrust  on  Triassic  to  Cretaceous  formations  and  involve  ver- 
tical displacements  of  8,000  to  12,000  feet  or  more  while  the  hori- 
zontal displacement  is  estimated  at  not  less  than  12  miles. 

ORE  DEPOSITS 

HISTORICAL  SKETCH  OF  MINING 

Although  gold  was  found  in  Deer  Lodge  county  as  early  as 
1852,  the  first  important  discovery  of  metallic  wealth  in  Montana 
was  the  discovery  of  placer  gold  at  Bannack  in  August,  1862.  Be- 
fore the  end  of  the  year  over  400  people  had  rushed  to  the  new 
“diggings”.  However,  after  the  discovery  of  the  rich  gulch  near 
Virginia  City,  Montana,  in  1868,  placer  mining  was  practically 
abandoned  at  Bannack  until  after  the  completion  of  the  Smith  and 

27.  Dunn,  William,  personal  communication. 

28.  Emmons,  W.  H.,  and  Calkins,  F.  C.,  op.  cit.  p.  146. 

29.  Willis,  Bailey,  Bull.  Geol.  Soc.  American,  vol.  13,  pp.  305-352,  1902. 

30.  Richards,  R.  W.,  and  Mansfield,  G.  R.,  Bull.  Geol.  Soc.  America,  vol.  23,  p.  675,  1913. 


MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


Bulletin  6,  Plate  VII 


A.  MADISON  LIMESTONE  OVERLYING  FOLDED  “RED  BEDS.” 


B.  MINOR  FOLDING  DEVELOPED  ALONG  FAULT  IN  THE  S.W.1^  OF  SEC.  9. 


T*LL'toiHr 

HMsJrt  m 

nf  tolH9ll 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA 


27 


Graeter  ditch  in  1866.  This  company  furnished  water  to  the  miners 
at  the  high  rate  of  75c  per  miner’s  inch.  This  ditch  proved  inade- 
quate to  work  the  bench  gravels,  so  the  Bannack  Mining  and  Ditch 
Company  constructed  a 30-mile  ditch  at  a cost  of  $35,000;  and 
shortly  afterward,  the  Pioneer  ditch,  10  miles  long,  was  constructed 
to  work  the  bench  gravels  north  of  Bannack.  By  1870  two  other 
ditches  had  been  completed:  White’s  ditch,  which  took  water  out 
of  Grasshopper  Creek  to  work  the  bars  below  Bannack,  and,  the 
Canyon  ditch,  also  from  Grasshopper  Creek,  to  work  the  Bon  Accord 
placers. 

The  construction  of  these  ditches  renewed  the  placer  mining 
activities  for  awhile,  but  it  was  cnly  a matter  of  time  until  all  the 
suitable  ground  was  worked  over.  The  placer  production  gradually 
declined  until  the  spring  of  1895,  when  a gold  dredge,  the  Fielding 
L.  Graves,  was  launched  near  Bannack.  This  was  the  first  success- 
ful gold  dredge  launched  in  the  United  States.31  It  was  electrically 
operated  and  had  a capacity  of  600  yards  per  day.  In  the  richest 
ground  this  dredge  took  out  $22,000  in  one  week  and  $38,000  the 
following  week.32  The  Molly  A.  Gibson,  the  second  successful  dredge, 
was  launched  in  the  fall  of  1895,  just  north  of  the  Excelsior  mine. 
The  A.  F.  Graeter  was  launched  May  23,  1896.  It  recovered  about 
$200,000  in  the  first  year,  which  paid  for  itself  and  the  placer 
ground  on  which  it  operated.  A fourth  dredge  was  launched  at 
Bon  Accord  a short  time  later.  The  fifth  dredge,  the  Coast,  was 
built  2 or  3 miles  below  Bon  Accord  but  capsized  when  it  was 
launched. 

The  first  quartz  mine  in  Montana,  the  Dakota,  was  located  in 
1862.  The  claims  were  located  according  to  the  local  mining  rules 
and  regulations  of  186233,  which  provided  that  the  claims  be  limited 
to  100  feet  along  the  lode  and  25  feet  on  either  side.  The  numerous 
small  claims  and  divers  ownerships  led  to  confusion,  and  inefficient 
mining.  The  Wadams,  Excelsior,  Wallace  and  numerous  other  gold 
properties  were  located  shortly  after  the  Dakota. 

The  first  quartz  mill  was  built  in  1862-63,  by  Allen  and  Arnold 
to  treat  the  Dakota  ore.  It  was  a 6-stamp  mill,  entirely  hand-made, 
and  was  driven  by  water  power.  The  first  steam-operated  stamp- 
mill,  with  24  stamps,  was  built  by  Butterfield  and  Hopkins  in  1864, 
at  a cost  of  $25,000.  Three  other  mills  were  built  before  1870.  The 
cost  of  treating  ore  in  these  mills  was  about  $4  per  ton.  All  these 

31.  Jennings,  Hennen  : The  history  and  development  of  gold  dredging  in  Montana. 

U.  S.  Bureau  of  Mines,  Bull.  121,  1916. 

32.  This  information  was  kindly  furnished  by  Mr.  F.  L.  Graves  of  Bannack. 

33.  Noyes,  A.  J.  : Dimsdale’s  Vigilantes  of  Montana,  p.  222,  1915. 


28 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


mills  have  been  dismantled.  In  1914  a cyanide  mill  of  200  tons 
capacity  was  constructed  by  the  Bannack  Gold  Mining  and  Milling 
Company.  It  ran  only  for  a short  period  and  has  since  been  idle. 
A stamp-mill  was  built  on  the  Hendricks  property  in  1920,  and 
operated  for  about  two  years. 

The  silver  mines  of  the  Blue  Wing  mining  district  were  dis- 
covered in  1864.  Although  rich,  the  ore  was  not  free  milling.  Some 
of  it  was  shipped  to  Wales  for  treatment,  but  after  the  construction 
of  the  smelters  at  Argenta  and  Bannack  most  of  it  was  treated 
locally.  In  1868  three  smelters  were  in  operation:  one  at  Ban- 
nack, one  at  Argenta,  and  a third  on  Taylor  Creek,  between  Ban- 
nack and  Argenta.  Eaton34  estimates  that  the  smelting  cost  was  at 
least  $38  per  ton,  and  Keyes35  estimates  that  ore  of  less  value  than 
$100  per  ton  could  not  be  profitably  smelted. 

The  mines  at  Bannack  have  been  worked  intermittently  in 
recent  years,  largely  by  lessees,  and  have  produced  considerably 
from  time  to  time.  Thus  within  the  last  15  years  Mr.  William  Dunn 
has  mined  about  $200,000  worth  of  ore  and  shipped  about  $100,000 
from  the  old  dumps. 

PRODUCTION 

The  total  production  of  the  region  including  the  yield  in  placer 
gold,  lode  gold,  and  silver  is  not  accurately  ascertainable  but  is 
estimated  to  be  about  $12,000,000.  Mr.  William  Dunn,36  who  is  prob- 
ably most  familiar  with  past  production  records,  estimates  the  total 
placer  production  of  the  Bannack  region  to  be  roughly  $8,000,000. 
Mr.  Carl  Hand,37  who  was  associated  with  mining  activities  at  Ban- 
nack, both  as  mine  superintendent  and  private  operator,  for  a num- 
ber of  years,  estimates  the  lode  gold  production,  excluding  that  of 
the  Hendricks  mine,  to  be  over  $2,000,000.  The  silver  production, 
chiefly  from  the  Blue  Wing  mining  district,  probably  did  not  exceed 
$2,000,000.08  Placer  mining  in  the  region  is  now  insignificant, 
probably  yielding  not  over  $1,000  yearly,  while  lode  production 
varies  from  a few  thousands  yearly  to  as  much  as  $100,000,  de- 
pending largely  upon  the  activity  of  the  lessees. 

MINERALOGY  OF  THE  ORES 

Gold  and  silver  minerals  are  the  most  important  in  the  ores 
of  the  Bannack  region,  although  minor  amounts  of  lead,  zinc  and 

34.  Mineral  Resources  of  the  States  and  Territories  we6t  of  the  Rocky  Mountains  for  1868,  p.  496. 

35.  Op.  cit.  Appendix,  p.  55. 

36.  Personal  communication. 

37.  Private  report. 

38.  This  figure  is  considerably  less  than  Winchell’s  estimate,  but  is  believed  by  the  writer  to  be 

a reasonable  one. 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA 


29 


copper  are  produced.  Practically  all  the  gold  has  come  from  the 

Bannack  mining  district.  The  Blue  Wing  district  has  produced 

most  of  the  silver. 

ORE  MINERALS 

The  following  minerals  which  occur  in  the  Bannack  district 

are  arranged  according  to  Dana’s  classification: 

Gold , native  gold  is  found  throughout  the  Bannack  region.  It  occurs 
both  in  the  placers  and  lode  deposits  at  Bannack  and  is  found 
in  small  amounts  in  the  ores  of  the  Blue  Wing  district. 

Silver , native  silver  has  been  reported  as  occurring  in  the  Golden 
Leaf  mines  and  probably  occurs  associated  with  the  silver  ores 
of  the  Blue  Wing  district. 

8 tib >iitc . antimony  sulphide,  is  found  at  the  Del  Monte  mine,  where 
it  occurs  as  needle-like  crystals  in  a quartz  gangue. 

Tetrad y mite,  bismuth  telluride,  is  found  in  the  gold  ores  of  the  Ban- 
nack district.  It  is  particularly  abundant  in  the  Excelsior  and 
Gold  Bug  ores  where  it  has  been  known  as  a gold  telluride.  In 
appearance  it  resembles  graphite.  Metallic  gold  can  usually  be 
seen  scattered  through  it,  even  in  hand  specimens. 

Galena , lead  sulphide,  is  widely  distributed  but  rarely  occurs  in 
amounts  sufficient  to  constitute  a valuable  lead  ore.  A good 
grade  of  galena  ore  was  encountered  on  the  lower  level  of  the 
Kent  mine. 

Argentite.  silver  sulphide,  has  been  recognized  in  both  the  Bannack 
and  Blue  Wing  districts. 

Jalpaite . a finely  disseminated  mineral  with  microchemical  reac- 
tions corresponding  with  those  of  jalpaite  was  noted  in  the 
ores  from  the  Kent  mine.  Jalpaite  is  a copper-bearing  silver 
sulphide. 

Sphalerite,  zinc  sulphide,  is  found  in  considerable  amounts  in  the 
silver  ores  of  the  Blue  Wing  district. 

Covcllite,  copper  sulphide  (CuS),  occurs  in  small  amounts  as  a secon- 
dary mineral  at  the  Kent  mine. 

Clialco  pyritc,  copper  iron  sulphide,  is  found  in  most  of  the  sulphide 
ores  in  the  Bannack  region. 

Pyrite , iron  sulphide,  is  probably  the  commonest  sulphide  mineral 
in  the  Bannack  region.  It  is  found  in  all  the  mines. 

Jamesonite.  lead  antimony  sulphide,  occurs  at  the  Kent  and  New 
Departure  mines. 

Pyrargyrite,  silver  antimony  sulphide,  has  been  noted  in  the  sulphide 


30 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


ores  at  the  Del  Monte  and  Kent  mines.  It  was  an  important  ore 
mineral  at  the  Del  Monte  mine. 

Tetrahedrite,  copper  antimony  sulphide,  (gray  copper) , occurs  in 
considerable  amounts  at  the  Kent,  Del  Monte  and  New  De- 
parture mines. 

Polybasite,  silver  antimony  sulphide,  was  noted  in  polished  sections 
of  the  Del  Monte  ore. 

Cerargyrite,  silver  chloride,  (horn  silver),  is  found  in  the  oxidized 
silver  ores  of  the  Blue  Wing  district. 

* Bromyritm,  silver  bromide,  and  embolite,  silver  chloro-bromide,  have 
been  reported  in  association  with  cerargyrite,  but  their  occur- 
rence has  not  been  proved  positively  in  the  oxidized  ores  of  the 
Blue  Wing  district. 

Stibiconite,  yellowish  antimony  oxide,  is  found  as  an  oxidation  prod- 
uct in  the  antimony  ores  at  the  Del  Monte  mine. 

Melaconite,  black  copper  oxide,  is  found  in  the  ores  of  the  Golden 
Leaf  mines.  Considerable  amounts  of  it  occur  in  a stope  near 
the  collar  of  the  Priscilla  winze  in  the  Golden  Leaf  mine. 

Psilomelane,  a small  deposit  of  this  hard  black  manganese  dioxide 
occurs  at  the  New  Departure  mine.  Some  of  the  material  has 
been  shipped  as  a manganese  ore. 

Smithsonite,  zinc  carbonate,  is  known  to  occur  in  the  oxidized  ores 
of  the  Kent  and  Del  Monte  mines. 

Cerussite,  lead  carbonate,  is  a common  mineral  in  the  oxidized  ores 
of  the  Blue  Wing  district.  It  is  an  important  ore  mineral  at 
the  Kent  mine. 

Malachite , the  green  basic  copper  carbonate,  is  a common  oxidation 
product  in  nearly  all  of  the  mines  of  the  region. 

Azurite , the  blue  basic  copper  carbonate,  was  noted  at  the  gold  mines 
at  Bannack  and  at  the  Kent  and  New  Departure  mines  in  the 
Blue  Wing  district. 

Calamine,  zinc  silicate,  was  noted  as  drusy  coatings  and  as  aggre- 
gates of  needle-like  crystals  in  the  oxidized  ores  of  the  Kent 
mine. 

Chrysocolla,  copper  silicate,  ranging  in  color  from  light  green  to 
dark  brown,  occurs  in  the  oxidized  ores  of  the  Bannack  mines. 

Bindheimite,  a hydrous  antimonate  of  lead,  is  found  as  yellowish  or 
greenish-yellow  waxy  and  earthy  material  at  the  Kent  and 
New  Departure  mines. 

*The  time-worn  myth  of  silver  “bromides”  dies  hard.  Unless  the  presence  of  bi-omine  can  be 
established  beyond  a doubt,  it  is  safe  to  assume  that  these  greenish-stained  silver-bearing 
minerals  are  derived  from  ai'gentiferous  tetrahedrite,  and  are  merely  silver  chloride  colored 
by  copper  carbonate. — F.  A.  T. 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA 


31 


Anglesite,  lead  sulphate,  is  found  in  the  oxidized  ores  of  the  Blue 
Wing  district.  It  is  an  important  ore  mineral  at  the  Kent  mine. 

Caledonite,  a basic  sulphate  of  lead  and  copper,  was  noted  as  a light 
blue  waxy  material  at  the  Kent  mine. 

Li  norite , an  azure  blue  basic  sulphate  of  lead  and  copper,  occurs  in 
small  amounts  at  the  Kent  mine. 

Wulfenite,  lead  molybdate,  occurs  sparingly  in  vugs  as  orange-red 
crystals  at  the  New  Departure  mine. 

GANGUE  MINERALS 

Sulphur  in  the  native  form  is  found  in  the  Golden  Leaf  mines  where 
it  occurs  massive  and  as  drusy  coatings. 

Quartz  is  the  most  wide  spread  and  abundant  gangue  mineral.  It  is 
found  in  all  of  the  mines  in  the  region. 

Hematite , the  specular  iron  oxide,  occurs  as  a primary  mineral  in 
the  gold  ores  at  Bannack.  Red  earthy  hematite  is  found  in  the 
outcrops  of  the  ores  throughout  the  region. 

Magnetite , magnetic  iron  oxide,  occurs  in  considerable  amounts  in 
the  contact  metamorphic  deposits  in  the  Bannack  vicinity. 

Pyrolusite,  the  soft  black  manganese  dioxide,  is  found  in  all  of  the 
oxidized  outcrops  of  the  Blue  Wing  district.  It  also  occurs  as 
needle-like  crystals  in  veinlets  cutting  psilomelane  at  the  New 
Departure  mine. 

1 Anionite,  the  name  limonite  is  here  applied  to  all  of  the  brown 
earthy  iron  oxides  of  the  district.  It  is  the  most  widely  dis- 
tributed mineral  in  the  oxidized  outcrops. 

Galcite,  calcium  carbonate,  is  one  of  the  most  common  gangue  min- 
erals in  the  region.  It  is  found  in  the  ores  of  all  the  mines. 

Sidcrite , iron  carbonate,  occurs  as  a gangue  mineral  in  the  ores  of 
the  Blue  Wing  district. 

Rhodochrosite , manganese  carbonate,  was  observed  in  the  sulphide 
ores  at  the  Kent  mine. 

Garnet , garnets  are  common  gangue  minerals  in  the  gold  ores  at 
Bannack. 

Vesuvianite > a basic  silicate  of  calcium  and  aluminum,  is  found  in 
the  contact  metamorphic  deposits  at  Bannack. 

Epidote,  a dark  green  complex  silicate,  is  a common  mineral  in  the 
gold  deposits  at  Bannack. 

Chlorite , the  fine-grained  green  mica  is  a common  gangue  mineral 
in  the  gold  ores  at  Bannack. 

Gypsum,  hydrous  calcium  sulphate,  is  found  in  the  Golden  Leaf 
mines  as  a secondary  mineral. 


32 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


BLUE  WING  MINING  DISTRICT 

The  Blue  Wing  mining  district  is  in  the  northern  part  of  the 
Bannack  area  (PL  I).  The  ore  bodies  of  this  district  occur  pre- 
dominantly as  replacement  veins39  in  limestone  and  granodiorite. 
Most  of  the  production  has  come  from  the  deposits  in  limestone. 
All  the  deposits  in  limestone  lie  close  to  the  contact  of  the  limestone 
with  the  granodiorite.  The  close  proximity  of  the  intrusive  contact 
and  the  replacement  silver  deposits  suggests  the  granodiorite  as 
the  source  of  the  ore  in  the  Blue  Wing  mining  district. 

The  ore  minerals  in  the  Blue  Wing  mining  district  include  gold, 
silver,  stibnite,  galena,  argentite,  jalpaite,  sphalerite,  covellite,  chal- 
copyrite,  pyrite,  pyrargyrite,  tetrahedrite,  polybasite,  ceragyrite, 
bromyrite  (?),  stibiconite,  pyrolusite,  hematite,  limonite,  psilome- 
lane,  smithsonite,  cerussite,  malachite,  azurite,  chrysocolla,  cala- 
mine, mimetite,  bindheimite,  anglesite,  linarite  and  wulfenite.  The 
commoner  gangue  minerals  are  calcite,  quartz,  rhodochrosite  and 
siderite. 

KENT  MINE 

The  Kent  mine  is  located  near  the  head  of  Spring  Gulch,  about 
three  miles  northeast  of  Bannack.  The  claims  lie  within  secs.  28 
and  33,  T.  7 S.,  R.  11  W.,  and  are  about  one-half  mile  south  of  the 
old  Bannack-Dillon  stage  road.  The  property  comprises  one  unpat- 
ented and  four  patented  claims. 

The  Kent  veins  were  located  in  186440  and  were  known  as  the 
Blue  Wing,  Kent,  and  Bannack  Chief.  These  were  the  first  silver 
deposits  located  in  Montana.  John  F.  O’Leary,  who  worked  the 
mines  successfully  during  the  ’sixties  and  ’seventies,  shipped  the 
ore  by  ox-team  to  the  Central  Pacific  railroad  at  Corrinne,  Utah, 
thence  by  rail  to  San  Francisco,  and  from  there  by  water  to  smelters 
at  Swansea,  Wales.  In  the  early  ’eighties  lessees  mined  ore  worth 
$68,000  within  a period  of  fourteen  months.  A short  time  later. 
Philip  Shenon*  acquired  a two-thirds  interest  in  the  property.  Mr. 
Shenon  ran  an  850-foot  tunnel  from  the  Edith  claim  into  the  hill 
between  the  Blue  Wing  and  Kent.  This  adit,  which  is  the  main 
entry  to  the  mine,  intersected  a body  of  lead-zinc  ore  near  the  con- 
tact between  the  intrusive  and  limestone  which  averaged  25  ounces 
in  silver  per  ton.  This  sulphide  deposit  is  known  as  the  “blind  lead”. 
In  1910,  S.  P.  Burr,  operating  under  a bond  and  lease,  exposed  a 

39.  Lingren,  Waldemar : Mineral  Deposits,  McGraw-Hill  Pub.  Co.,  N.  Y.,  pp.  69,  604,  1919. 

Also  Bull.  Geol.  Soc.  Amer.,  vol.  36,  pp.  247-262,  1925. 

40.  O’Leary,  John  F. : From  a report  written  in  1908. 

* Father  of  the  writer,  F.  A.  T. 


MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


Bulletin  6,  Plate  YIII 


MAP  OF  BLUE  WING  WORKINGS  OF  KENT  MINE 


rut 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA 


small  body  of  ore  in  the  Blue  Wing  workings  which  netted  approxi- 
mately $10,000.  Mr.  John  O’Leary  estimates  the  production  of  the 
Kent  property  to  be  approximately  $750,000. 

The  ores  of  the  Kent  mine  occur  as  shoots  along  fissures  in 
white  crystalline  limestone  and  as  veins  in  granodiorite  but  the 
deposits  in  limestone  alone  have  been  worked.  The  fissures  in  lime- 
stone strike  N.  80  degrees  E.  and  dip  70  degrees  N.  and  all  the  de- 
posits in  limestone  occur  a short  distance  from  the  granodiorite 
contact.  The  Kent  and  Whopper  ore  bodies  were  tabular  deposits 
along  well-defined  fissures.  The  Kent  ore-body  which  raked  to  the 
west  at  an  angle  of  about  20  degrees  was  the  largest  in  the  mine. 
The  Whopper  ore  body  was  an  irregular  deposit  along  the  Whopper 
fissure,  and  its  downward  extension  has  not  yet  been  found.  The 
Hayes  and  Ewing  ore-shoot  was  a pipe-like  deposit  occurring  at  the 
intersection  of  the  Blue  Wing  fissure  with  the  contact  of  a white 
marble  and  a dense  bluish-gray  limestone  (PL  VIII).  Above  the 
tunnel  a small  seam  of  ore  extended  out  along  the  fissure  to  the 
portal.  The  Burr  ore  shoot  was  a peculiar  winding  pipe  extending 
away  from  the  Hayes  and  Ewing  ore  body.  The  Kent  and  the 
Hayes  and  Ewing  stopes  average  from  8 to  10  feet  in  width,  but 
the  Whopper  was  considerably  narrower.  The  walls  of  the  ore 
bodies  are  usually  well  defined  although  the  ore  is  sometimes 
‘‘frozen”  to  the  walls.  The  limestone  for  several  feet  adjacent  to  the 
larger  ore  shoots  is  frequently  altered  to  a chocolate-brown  color 
and  sometimes  a gray  clay-like  casing  is  found  next  to  the  ore. 

The  veins  in  granodiorite  have  well-defined  walls  which  are 
frequently  slicken-sided.  The  ore  in  the  Shenon  tunnel,  known  as 
the  “blind  lead”,  is  exposed  by  crosscuts  for  a distance  of  170  feet. 
It  strikes  east  and  dips  about  30°  to  the  south.  The  ore  band  is 
associated  with  two  or  three  feet  of  gouge  impregnated  with  pyrite 
on  the  foot- wall  side.  The  ore  itself  is  cut  by  slicken-sided  fractures, 
the  result  of  post-mineral  movement.  The  relationship  between  the 
veins  in  granodiorite  and  those  in  the  limestone  could  not  be  ascer- 
tained because  of  the  condition  of  the  old  workings. 

The  chief  gangue  minerals  of  the  ores  in  limestone  are  quartz 
and  calcite  and  the  ore  minerals  include  galena,  tetrahedrite,  jame- 
sonite,  sphalerite,  covellite,  pyrite,  jalpaite  ( ?),  cerargyrite,  bind- 
heimite,  linarite,  caledonite,  cerussite,  anglesite,  malachite,  azurite, 
chrysocholla,  smithsonite,  calamite,  limonite,  and  manganese  oxides. 
Much  of  the  ore,  particularly  in  the  Kent  vein,  is  soft  porous  ma- 
terial predominantly  brown  in  color,  but  containing  green  and  yellow 


34 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


“splotches”  of  lead,  copper,  and  silver  minerals.  The  ore  from  the 
Blue  Wing  and  Whopper  veins  is  predominantly  greenish  and  yel- 
lowish in  color,  usually  well  indurated,  and  sometimes  waxy  in  ap- 
pearance. Because  the  harder  ore  is  sometimes  “frozen”  to  the 
walls  skillful  mining  is  required  to  prevent  heavy  losses. 

Residual  remnants  of  sulphide,  known  locally  as  “black  metal- 
lies”,  occur  in  the  oxidized  ore.  Pyrite  and  galena  are  the  oldest 
minerals  in  the  residual  patches.  The  pyrite  is  partly  oxidized  to 
limonite  and  the  galena  .shows  typical  alteration  to  anglesite  along 
cleavage  planes  (PI.  IX,  2).  The  tetrahedrite  and  jalpaite  (?)  ac- 
count for  the  very  high  silver  content  of  the  sulphide  patches.  The 
jalpaite  (?)  is  commonly  seen  replacing  pyrite.  Covellite  in  turn 
replaces  jalpaite  (?),  showing  splendid  intergrowths  and  replace- 
ment borders  (PI.  IX,  1).  Although  the  evidence  is  not  complete 
it  is  believed  that  the  jalpaite  (?)  and  covellite  are  both  supergene 
minerals.  Neither  are  known  in  the  sulphide  ore  of  the  “blind  lead.” 

The  sulphide  ore  in  the  granodiorite  is  in  a gangue  of  quartz 
and  calcite.  Galena,  sphalerite  and  pyrite  are  the  commonest  ore 
minerals  and  chalcopyrite  was  noted  as  inclusions  in  sphalerite. 
Pyrargyrite  is  visible  locally  and  probably  accounts  for  the  high 
silver  content  shown  in  some  of  the  assays.  Both  gangue  and  ore 
minerals  have  been  brecciated  and  re-cemented  but  the  galena  is 
sometimes  deformed  without  fracturing.  The  sulphide  ore  shows  no 
oxidation,  and  secondary  enrichment  only  locally.  In  1908  lessees 
made  a shipment  of  the  “blind  lead”  ore  from  near  the  contact  with 
the  limestone  which  gave  the  following  smelter  returns: 

Gold  Silver  Lead  Zinc  Silica  Iron  Sulphur 

0.09  oz.  29.7  oz.  1.5%  3.6%  40.2%  5.8%  11.8% 

Samples  from  the  ore-body  in  No.  2 crosscut  230  feet  east  of 
the  limestone  contact  gave  the  following  assays: 

Silver  Lead  Zinc 

17.4  oz.  30.1%  8.5% 

20.0  20.0  

38.5  32.4  19.0 

The  veins  in  the  limestone  which  were  readily  seen  at  the 
surface  have  been  mined  at  a handsome  profit,  nevertheless,  little 
search  has  been  made  for  new  deposits.  The  most  favorable  place 
to  prospect  for  high-grade  ore  is  along  the  contact  of  the  white 
marble  and  the  bluish-gray  limestone. 

DEL  MONTE  MINE 

The  Del  Monte  mine  is  in  sec.  28,  on  the  old  Bannack-Dillon 
stage  road,  about  a mile  northwest  of  the  Kent  mine.  The  property 


MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


Bulletin  6,  Plate  IX 


PHOTOMICROGRAPHS  OF  ORES  FROM  THE  KENT  AND  DEL  MONTE  MINES 

1.  Covellite  (dark  gray)  replacing  jalpaite  (?)  (white).  Fracture  filled  with  quartz.  Magnifica- 
tion 540  times. 

2.  Galena  (white)  being  replaced  along  cleavage  planes  by  anglesite  (gray).  Black  spots  are 
holes.  Magnification  50  times. 

3.  Tetrahedrite  (white)  partly  replaced  with  polybasite  (etched  with  cyanide).  The  gray  mineral 
with  euhedral  outlines  is  quartz.  Polished  section.  Magnification  14  times. 

4.  Stibnite  (black)  in  quartz  cut  by  a veinlet  of  later  quartz.  Thin  section.  Ordinary  light. 
Magnification  V times. 


m 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA 


35 


comprises  six  patented  claims,  and  is  owned  by  the  West  Butte  Min- 
ing Company. 

Very  little  was  learned  of  the  history  and  production.  Some 
early-day  shipments  were  made41  but  records  of  the  returns  are 
not  available.  Lessees  who  took  out  considerable  ore  in  the  late 
’nineties  are  said  to  have  netted  a profit.  One  of  the  cars  shipped 
averaged  over  500  ounces  in  silver  per  ton.  Since  these  lessees  sank 
a shaft  to  a depth  of  over  250  feet,  and  handled  considerable  water, 
besides  doing  a good  deal  of  drifting,  it  is  estimated  that  they  must 
have  taken  out  at  least  $30,000  and  probably  not  over  $50,000.  The 
West  Butte  Mining  Company  purchased  the  property  from  the 
Graves  estate  of  Bannack,  in  1922  and,  after  cleaning  out  and  re- 
timbering the  Del  Monte  shaft,  ran  a number  of  prospect  drifts, 
chiefly  on  the  upper  levels.  Prospecting  was  abandoned  after  a 
year’s  work,  and  the  property  has  since  been  idle. 

The  underground  workings42  with  the  exception  of  a few  tunnels 
and  open  cuts,  are  all  driven  from  the  Del  Monte  shaft,  which 
reached  a depth  of  253  feet.  At  present  the  shaft  is  full  of  water 
below  a depth  of  50  feet. 

The  ores  in  the  Del  Monte  mine  occur  chiefly  in  well-defined 
veins  in  granodiorite  which  strike  about  N.  80°  E.  and  dip  at  steep 
angles  to  the  south.  Veins  in  the  limestone  usually  have  a low 
silver  content  but  some  contain  small  deposits  of  high-grade  an- 
timony ore.  According  to  F.  M.  Wichman43  faulting  has  been  ex- 
tensive in  the  neighborhood  of  the  Del  Monte  mine.  The  faults 
trend  in  all  directions  but  the  northerly  and  northeasterly  ones  are 
the  most  prominent. 

Two  veins  in  the  granodiorite  have  been  mined,  the  Del  Monte 
and  the  Bonaparte.  The  Bonaparte  is  the  larger  but  is  lower  grade 
than  the  Del  Monte  vein,  and  is  said  to  assay  from  20  to  40  ounces 
in  silver  per  ton.  It  is  about  six  feet  wide  on  the  surface.  The  Del 
Monte  vein  ranges  in  width  from  4 to  14  inches  on  the  bottom 
level  and  averages  60  ounces  of  silver  per  ton.  Some  assays  run 
as  high  as  450  ounces. 

Near  the  surface  these  veins  are  much  oxidized  and  are  filled 
with  brownish  to  black  porous  material  consisting  largely  of  quartz 
with  oxides  of  manganese  and  iron.  Casts  of  the  original  minerals 
are  plainly  visible.  The  sulphides  appear  about  50  feet  beneath  the 
surface  and  in  the  lower  levels  no  evidence  of  oxidation  is  visible 
Sphalerite,  galena,  chalcopyrite,  pyrite,  polybasite,  tetrahedrite  and 

41.  Raymond,  R.  W. : Mineral  resources  west  of  the  Rocky  Mountains  for  1872,  1873,  and  1874. 

42-43.  Wichman,  F.  M.  : Letter  of  May  17,  1925. 


36  BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 

pyrargyrite  occur  in  a gangue  of  calcite,  rhodochrosite  and  quartz 
(PI.  IX,  3). 

Small  deposits  of  high-grade  antimony  ore  occur  on  the  Francis 
H.  claim  along  vertical  fissures  which  strike  N.  60°  E.  in  crystalline 
limestone.  Stibnite  is  found  in  quartz  gangue  (PL  IX,  4) , and  is 
associated  with  about  two  feet  of  a reddish-brown  gouge.  Slicken- 
sided  fractures  cutting  the  stibnite  give  evidence  of  post  mineral 
movement. 

NEW  DEPARTURE  MINE 

The  New  Departure  mine  is  situated  about  16  miles  southwest 
of  Dillon,  in  the  NW.14  of  sec.  26.  The  property  comprises  seven  pat- 
ented claims  but  the  Signal  and  Quien  Sabe  produced  all  the  ore. 
The  property  was  located  in  1871  by  George  W.  Stapleton44  who 
sold  it  to  Lawrence  A.  Brown  and  Joshua  E.  Clayton  in  1880  for 
the  sum  of  $2,500.  Brown  purchased  Clayton's  interest  seven  years 
later  for  $3,500,  and  operated  the  mine  continuously  until  the  time 
of  his  death  in  1905.  The  mine  was  then  sold  to  the  New  Departure 
Mining  Company  for  $50,000.  This  company  operated  for  two 
years,  having  as  many  as  forty  miners  working  at  one  time.  The 
property  was  then  operated  by  lessees  until  1918,  when  it  was  sold 
to  O.  M.  Best  of  Dillon.  John  Coppin  of  Dillon  worked  it  under  a 
bond  and  lease  agreement  until  1928,  when  it  was  sold  to  J.  L. 
Templeman  of  Butte.  The  mine  is  credited  with  a production  of 
over  a million  dollars. 

The  ore  bodies  at  the  New  Departure  mine,  which  strike  east- 
erly and  dip  south,  occur  chiefly  along  fractures  in  massive  bluish- 
gray  Madison  limestone.  Some  of  the  largest  deposits  are  found 
along  the  intersections  of  fractures.  The  FarrelLstope  rakes  down 
the  intersection  of  two  fractures.  Intersecting  northwest  and  north- 
east fractures  are  also  responsible  for  the  large  ore  body  at  the 
head  of  the  incline  in  the  Homeside  tunnel.  The  ore  shoots  com- 
monly terminate  on  the  lower  side  of  flat  slips  which  are  usually 
slickensided  and  striated  by  movement.  Thus  in  the  Badger  work- 
ings the  ore  which  stood  at  an  angle  of  about  45°  flattened  and 
pinched  out  after  reaching  a flat  slip.  Some  large  ore  bodies  have 
been  mined  just  beneath  the  slips,  after  the  ore  shoot  flattened. 

Cerargyrite,  cerussite,  bindheimite  and  other  oxidation  prod- 
ucts with  residual  patches  of  sulphides  composed  chiefly  of  sphale- 
rite, galena,  and  tetrahedrite  occur  in  a gangue  of  quartz  and  cal- 
cite. Argentite  (?),  smithsonite,  anglesite,  malachite,  azurite,  gyp- 


44.  Historical  date  was  supplied  by  John  Coppin  of  Dillon. 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA 


37 


sum  and  oxides  of  manganese  and  iron  occur  in  lesser  amounts,  and 
assays  indicate  the  presence  of  gold.  Wulfenite  occurs  in  small 
amounts. 

A small  deposit  of  high-grade  manganese  ore  occurs  just  be- 
low the  Stapleton  tunnel.  It  strikes  northeast  and  dips  to  the  south. 
Psilomelane  is  cut  by  small  veins  filled  with  fibrous  pyrolusite.  A 
small  deposit  of  oxidized  gold  ore  said  to  carry  $10  per  ton  in  gold 
was  found  just  north  of  this  deposit. 

HURON  MINE 

The  Huron  mine  is  just  north  of  the  Kent  and  comprises 
seven  claims  all  of  which  are  in  sec.  28.  The  claims  were  located 
in  the  ’sixties  by  a man  named  Batchelor  who  mined  considerable 
ore,  some  of  the  early  shipments  being  sent  to  Swansea.  The  prop- 
erty was  later  acquired  by  John  Costello  who  sold  a half  interest 
to  Frank  Sinnott  in  1910.  The  latter  became  the  sole  owner  after 
Costello’s  death.  Mr.  Sinnott  estimates  the  total  production  to  be 
about  $30. 000. 45 

The  deposits  at  the  Huron  mine  occur  as  replacements  along 
fissures  in  white  crystalline  limestone.  The  principal  fissures  strike 
east  and  dip  about  70°  to  the  south.  The  ores  are  similar  to  those 
of  the  Kent  mine.  Cerargyrite  with  patches  of  residual  sulphides 
occur  in  a gangue  of  quartz  and  calcite. 

POMEROY  MINE 

The  Pomeroy  mine  is  northwest  of  the  Del  Monte  mine  and  com- 
prises three  claims.  The  property  was  located  in  the  ’sixties  and  pro- 
duced considerable  ore  in  the  early  ’seventies.46  The  main  workings 
consist  of  an  incline  shaft  with  open  stopes  which  reach  the  sur- 
face. The  ore  which  occurs  in  a bluish-white  limestone  is  in  well- 
defined  fissures  which  strike  N.  80°  E.  and  dip  60°  N.  The  chief 
ore  mineral  is  lead  carbonate  which  carries  silver.  A red  gouge 
varying  in  thickness  from  2 to  4 feet  is  associated  with  the  ore. 

RANDALL  MINE 

The  Randall  mine  adjoins  the  Kent  mine  on  the  south.  It  in- 
cludes one  claim  and  is  owned  by  Mr.  H.  C.  Paddock  of  Bannack. 
The  property  was  located  in  the  ’sixties  and  has  produced  consid- 
erable ore  which  has  been  mined  chiefly  for  its  silver  content,  al- 
though considerable  galena  is  associated  with  it.  The  ore  occurs  as 
replacement  deposits  along  fissures  in  a white  crystalline  lime- 
stone which  strike  east.  The  shoots  terminate  against  a massive 
bluish-gray  limestone. 


45.  Sinnott.  P.  F..  Personal  communication. 

46.  Raymond.  R.  W..  Mineral  resources  west  of  Rooky  Mountains  for  1872.  p.  267. 


38 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


SILVER  STAR  MINE 

The  Silver  Star  mine  is  in  SW.%  of  sec.  33,  T.  7 S.,  R.  11  W., 
just  west  of  the  limestone-granodiorite  contact.  It  is  owned  by  the 
Monroe  Mann  estate.  The  ores  occur  as  replacements  in  veins  which 
strike  N.  50°  W.  and  dip  60°  to  the  south  and  along  bedding  planes 
in  flat-lying  Madison  limestone.  The  ore  is  chiefly  oxidized  ma- 
terial and  is  reddish-brown  in  color  with  occasional  green  and  yel- 
low patches  of  copper  and  silver  minerals. 

INGERSOLL  MINE 

The  Ingersoll  mine  lies  just  south  of  the  Silver  Star  in  sec.  4, 
T.  8 S.,  R.  11  W.  and  includes  three  claims.  It  is  owned  by  the  Amede 
Bessette  estate  of  Bannack.  The  property  was  discovered  in  the 
’sixties  and  is  credited  with  considerable  early-day  production,  from 
open  cuts  and  tunnels.  In  1912  Phillip  Lonergran,  working  under  a 
bond  and  lease,  sank  a winze  to  a depth  of  about  200  feet.  This 
winze  crossed  the  contact  between  the  limestone  and  granodiorite 
and  was  extended  into  the  granodiorite  for  some  distance/'  A tun- 
nel 150  feet  in  length  connects  the  Lonergran  winze  with  the  sur- 
face. This  tunnel  was  driven  its  entire  length  in  a white  limestone 
gouge.  The  ore  deposits  occur  as  replacement  veins  in  a white  lime- 
stone and  strike  east.  The  ore  minerals  which  occur  in  a quartz  and 
calcite  gangue  include  cerussite,  cerargyite,  bromyrite  (?),  and 
malachite. 

CHARTER  OAK  MINE 

The  Charter  Oak  mine,  which  is  south  of  the  Ingersoll,  was 
located  in  the  ’sixties  and  has  produced  considerable  ore.  It  is  owned 
by  Foy  Herr  of  Bannack.  The  ore  occurs  as  replacement  veins  in  a 
white  crystalline  limestone  and  includes  oxidized  silver  and  lead 
minerals  in  a quartz  and  calcite  gangue. 

WHEAL  ROSE  MINE 

The  Wheal  Rose  property  is  in  sec.  27,  T.  7 S.,  R.  11  W.,  and  is 
owned  by  Archie  Gibson  and  the  Graves’  estate  of  Bannack.  It  is 
credited  with  some  production.  The  ore  occurs  along  fissures  in 
Madison  limestone  which  strike  east.  The  ore  minerals  include 
cerargyrite  and  cerussite  in  a gangue  of  quartz  and  calcite. 

IRON  MASK  MINE 

The  Iron  Mask  mine  is  in  the  SW.14  of  sec.  28,  T.  7 S.,  R.  11  W. 
Little  was  learned  of  the  history  and  production,  although  it  is 
known  that  ore  was  shipped  in  the  early  days.  The  main  entrance 
is  a shaft  which  is  said  to  have  reached  a depth  of  200  feet.  The 
ore  is  in  well-defined  veins  in  granodiorite  which  strike  east.  Near 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA 


39 


the  surface  the  ore  is  composed  largely  of  black  porous  material 
consisting  predominantly  of  quartz  and  calcite  with  oxides  of  man- 
ganese and  iron.  Sulphides  are  reported  in  the  lower  workings.  On 
the  surface  the  Iron  Mask  vein  resembles  those  of  the  Del  Monte, 
but  no  specimens  were  secured  from  the  lower  levels. 

BANNACK  MINING  DISTRICT 

The  Bannack  mining  district  is  in  the  southern  part  of  the 
Bannack  area  (PI.  1).  The  ore  deposits  are  at  or  near  the  contact 
between  granodiorite  and  limestone  and  occur  chiefly  along  or  near 
the  apex  of  apophyses  (granodiorite  outliers)  which  extend  into  the 
limestone.  Well-defined  fracturing  appears  above  and  in  front  of 
the  apophyses,  as  illustrated  by  the  mineralized  fractures  in  the 
Excelsior  mine  and  in  the  Dollar  winze  and  Green  raise  of  the 
Wadams  mine.  The  fact  that  ore  bodies  are  present  along  or  at  the 
apexes  of  the  apophyses  suggests  that  the  apophyses  were  intruded 
along  zones  of  weakness  or  that  their  intrusion  caused  the  fractur- 
ing, which  permitted  ready  access  to  mineralizing  solutions.  Al- 
though some  rich  deposits  distant  from  the  contact  have  been 
mined,  the  largest  and  most  important  ones  occur  as  irregular 
bodies  in  limestone  near  the  contact  with  the  granodiorite.  These 
deposits  which  are  almost  entirely  oxidized  in  some  of  the  mines, 
are  found  in  greater  abundance  on  the  limestone  side  of  the  garnet 
zones.  According  to  Umpleby48  this  relationship  is  a general  one. 
Since  fractures  containing  ore  were  observed  cutting  both  limestone 
and  garnet  rock  it  is  believed  that  the  ore  minerals  were  introduced 
after  the  garnetization.  Bodies  of  magnetite  and  some  pyrite  and 
chalcopyrite  were  observed  in  the  garnet  zone.  Lindgren49  states 
that  the  silicates  and  magetite  are  earlier  than  the  sulphides  in 
contact  deposits  but  that  the  periods  of  deposition  overlap.  The 
presence  of  garnet,  vesuvianite  and  certain  other  minerals  suggests 
that  the  deposits  at  Bannack  were  formed  under  conditions  of  high 
temperature  and  pressure50  although  specularite  is  present  the 
favorable  temperature  for  the  formation  of  which  in  contact  de- 
posits is  supposed  to  be  about  490°. 51 

The  ore  minerals  in  the  Bannack  mining  district  include : native 
gold,  tetrahedrite,  argentite,  cerargyrite,  tetradymite,  galena,  cerus- 
site,  anglesite,  sphalerite,  chalcopyrite,  tenorite,  chrysocolla,  azurite, 
melanconite,  native  sulphur,  pyrite,  specularite,  magnetite,  iron  and 

47.  Sinnott,  F.  F.  : Personal  communication. 

48.  Umpleby,  J.  B.,  Univ.  of  Calif.  Pub.  in  Geol.,  p.  25,  1916. 

49.  Lindgren,  Waldem&r  : Mineral  deposits,  p.  718,  McGraw-Hill  Pub.  Co.,  N.  Y.,  1919. 

50.  Emmons,  W.  H.  : Principles  of  Economic  Geology,  p.  44.  McGraw-Hill  Pub.  Co.,  N.  Y.,  1918. 

51.  Butler,  B.  S.  : Economic  Geology,  vol.  10,  p.  400,  1923. 


40  BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 

manganese  oxides.  The  gangue  minerals  include  quartz,  calcite, 
chlorite,  garnet,  siderite,  epidote  and  vesuvianite. 

THE  BANNACK  GOLD  MINING  AND  MILLING  COMPANY 

The  Bannack  Gold  Mining  and  Milling  Company  owns  14  lode 
claims  and  five  placer  claims  in  the  Bannack  mining  district.  Most 
of  the  production  has  come  from  the  Excelsior,  Blue  Grass,  and  the 
Golden  Leaf  group,  (which  includes  the  Wadams,  Wallace  and  Gold- 
en Leaf  claims).  All  of  the  claims  were  located  in  the  'sixties  and 
’seventies,  most  of  them  under  the  early-day  mining  regulations 
which  provided  that  claims  be  limited  to  100  feet  along  the  lode 
and  25  feet  on  either  side.  All  have  since  been  relocated  in  accord- 
ance with  the  Federal  laws.  Philip  Shenon,  who  operated  the  mines 
for  a number  of  years,  sold  the  properties  to  the  Golden  Leaf  Co., 
Inc.,  in  the  ’nineties.  This  company  in  turn  sold  to  the  Great  West- 
ern Mines  & Exploration  Co.,  and  the  latter  sold  to  the  present  own- 
ers in  1910.  The  Bannack  Gold  Mining  and  Milling  Co.  did  consid- 
erable exploration  work  and  constructed  a 200-ton  cyanide  mill. 
This  mill  operated  for  but  a short  time.  In  1930,  the  I.  B.  Mining 
Co.  was  operating  the  Golden  Leaf  group  under  a bond  and  lease 
agreement. 

EXCELSIOR  MINE 

The  Excelsior  mine  is  near  the  eastern  border  of  the  granodio- 
rite  intrusive.  The  ore  shoot  has  been  mined  to  a depth  of  about 
300  feet  and  has  produced  approximately  $300, 000.52  The  old  shaft 
is  now  inaccessible.  The  Excelsior  ore  body  occurred  at  the  contact 
between  crystalline  limestone  and  granodiorite ; at  the  apex  of  a 
granodiorite  aphophysis.  The  limestone  granodiorite  contact  at  the 
mines  strikes  N.  35°W.  and  dips  about  45°W.  The  stope  at  the 
tunnel  level  extends  for  about  30  feet  along  the  contact  and  is  about 
8 feet  in  width.  Intense  garnetization  had  taken  place  near  the 
contact.  The  garnet  is  clear  citron-brown  in  color,  in  contrast  to 
that  in  the  Golden  Leaf  mine,  of  a dull  reddish-brown  color.  Coarse 
crystalline  calcite  and  speeularite  are  associated  with  the  garnet. 
The  gold  is  either  free  or  in  tetradymite  and  is  found  in  a light 
green  gangue  composed  chiefly  of  calcite,  chlorite,  garnet,  specu- 
larite  and  some  quartz.  The  ore  shoot  occurring  chiefly  on  the 
limestone  side  of  the  garnet  zone  was  offset  to  the  southwest  by  a 
series  of  step  faults53  in  the  lower  workings. 


52.  Hand,  Carl : Private  report. 

53.  Dunn,  William  : Personal  communication. 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA 


41 


GOLDEN  LEAF  GROUP 

The  Golden  Leaf  group,  including  the  Wadams,  Wallace,  and 
Golden  Leaf  claims,  is  at  the  western  border  of  the  granodiorite 
contact.  The  mines  are  all  connected  by  raises  and  ore  can  be  de- 
livered to  the  mill  from  any  of  the  workings  through  the  tunnel 
known  as  the  Priscilla  level.  The  difference  in  elevation  between 


FIGURE  2.  MAP  SHOWING  INTRUSIVE  RELATIONS  ON 
WALLACE  LEVEL  OF  WADAMS  MINE. 


the  Priscilla  level  and  the  upper  workings  of  the  Wadams  mine  is 
about  475  feet.  The  Dunn  level,  which  is  reached  through  an  in- 
clined winze  is  about  140  feet  below  the  Priscilla  level.  Mr.  Hand 
estimates  the  production  of  the  Golden  Leaf  group  to  be  about 
$1,320,000.54 

The  ore  deposits  are  in  a white  or  bluish-white  crystalline  lime- 


54.  Hand,  Carl : op.  cit. 


42 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


stone  at  or  near  the  contact  with  the  granodiorite.  Some  of  the  best 
deposits  occur  along  apophyses  which  extend  out  into  the  lime- 
stone. The  deposits  in  the  Wadams  and  Wallace  mines  are  of  this 
type  (Fig.  2) . The  limestone  is  usually  intensely  garnetized  near 
the  contact  with  the  granodiorite.  The  ore,  which  lies  predominantly 
outside  of  the  garnet  zones,  is  almost  entirely  oxidized  in  the  upper 
levels  but  the  sulphides  become  more  prominent  in  the  lower  levels. 
A large  body  of  sulphide  ore,  about  15  feet  wide,  consisting  largely 
of  pyrite  with  lesser  amounts  of  chalcopyrite,  occurs  in  an  intensely 
garnetized  limestone  in  one  of  the  crosscuts  off  the  Priscilla  level. 
The  relative  insolubility  of  the  garnet  gangue  may  account  for  the 
fact  that  these  sulphides  are  quite  fresh,  although  ore  bodies  in 
limestone  on  the  same  level  are  highly  oxidized.  Chalcopyrite  and 
pyrite  occur  on  the  Dunn  level  in  a dark  green  gangue  composed 
largely  of  calcite  and  chlorite  with  lesser  amounts  of  quartz,  epidote 
and  specularite  (PI.  X,  4) . Native  gold  with  calcite  was  observed 
along  fractures  in  the  chalcopyrite  (PI.  X,  3).  Partly  oxidized  ga- 
lena ore  carrying  silver  occurs  on  the  Priscilla  level  and  deposits 
of  magnetite  were  noted  in  several  places  along  the  limestone- 
diorite  contact. 

The  ore  minerals  include  native  gold,  tetrahedrite,  chalcopyrite, 
malachite,  azurite,  chrysocolla,  tenorite,  galena,  cerussite,  anglesite, 
sphalerite,  smithsonite,  native  sulphur,  pyrite,  specularite,  magne- 
tite, limonite,  and  manganese  oxides.55  The  gangue  minerals  include 
calcite,  quartz,  siderite,  garnet,  epidote  and  vesuvianite. 

BLUE  GRASS  AND  GOLD  BUG  MINES 

The  Blue  Grass  mine  is  owned  by  the  Bannack  Gold  Mining 
and  Milling  Company  and  the  Gold  Bug  is  owned  by  the  Graves’ 
estate  of  Bannack.  The  claims  include  a number  of  the  earliest 
locations  in  the  Bannack  district.  The  Gold  Bug  embraces  the 
original  Dakota  locations.  Mr.  Hand  estimates  the  production  of 
these  properties  to  be  about  $550, 000.56 

The  ore  deposits  are  at  or  near  the  contact  of  a white  crystal- 
line limestone  with  a small  tabular  body  of  granodiorite.  The  lime- 
stone, which  is  intensely  garnetized  near  the  contact,  contains 
abundant  specularite.  The  ore  is  found  predominantly  outside  of 
the  garnet  zone.  These  deposits  occur  in  a region  of  minor  folding 
and  faulting.  Gold  in  a quartz  and  calcite  gangue  or  in  tetrady- 
mite,  (PI.  X,  1 and  2),  is  the  most  important  metal  but  assays  show 
the  presence  of  silver.  In  1925  Mr.  Austin  Hale  opened  a pipe-like 


55.  Shenon,  P.  J. : Gold  at  Bannack,  Montana,  Eng.  & Min.  Jour.,  vol.  123,  p.  326,  1927. 

56.  Hand,  Carl : op.  cit. 


MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


Bulletin  6,  Plate  X 


3 


4 


PHOTOMICROGRAPHS  OR  ORES  FROM  THE  BANNACK  DISTRICT,  MONTANA. 

1 and  2.  Native  gold  (white)  in  tetradymite  (gray)  showing  tendency  of  the  gold  to  follow  part- 
ing planes.  Tetradymite  etched  with  nitric  acid.  Note  structures  developed  by  etching.  (Gold 
Bug  mine.)  Magnification  14  times. 

3.  Gold  (white)  occurring  along  fracture  in  chalcopyrite  (light  gray).  Surface  etched  with  nitric 
acid.  Calcite  associated  with  the  gold  along  fracture  (black)  was  removed  by  the  acid.  (Dunn 
level,  Golden  Leaf  mine.)  Magnification  110  times. 

4.  Specularite  (with  radiating  structure)  in  quartz  (dark  gray)  terminating  against  pyrite. 
(Dunn  level,  Golden  Leaf  mine.)  Magnification  14  times. 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA  43 

deposit  of  granular  pyrite  which  carried  about  $30  in  gold,  and  in 
1927  some  work  was  done  by  C.  W.  Stalling.  This  deposit  strikes 
N.  50°  W.,  and  rakes  to  the  north  at  an  angle  of  about  25  degrees. 

HENDRICKS  MINE 

The  Hendricks  mine  is  about  a quarter  of  a mile  south  of  Ban- 
nack  and  on  the  opposite  side  of  Grasshopper  Creek.  Two  claims 
are  included  in  the  group,  the  Hendricks  and  the  Suffield.  Although 
the  property  was  first  located  during  the  early  days  of  Bannack, 
little  ore  was  produced  until  1918,  when  the  Bannack  Mining  and 
Milling  Company,  operating  under  a bond  and  lease,  put  up  a 
5-stamp,  amalgamation  mill.  A small  ball-mill,  a classifier  and  two 
cyanide  tanks  were  added  in  1919.  In  1920  a new  10-stamp  mill  was 
built.  It  contained  a ball-mill,  a classifier,  two  agitators,  four  thick- 
eners and  six  cyanide  tanks  and  had  a capacity  of  50  tons  in  24 
hours.  This  mill  was  closed  down  in  1921.  The  underground  work- 
ings include  about  1,500  feet  of  drifts  and  one  50-foot  winze.  The 
property  is  now  owned  by  the  Graeter  Park  Realty  Company  of 
Dillon. 

The  ore  occurs  as  shoots  along  bedding  planes  in  limestone  of 
Madison  age  which  has  undergone  considerable  minor  folding.  The 
ore  of  milling  grade  was  in  six  different  shoots  within  a distance 
of  200  feet,  although  the  mineralization  was  continuous  through- 
out.57 Only  one  of  the  ore  bodies  came  down  as  far  as  the  working 
level.  The  shoots  raked  about  7°  N.  and  dipped  from  65°  W.,  to 
less  than  20°  W.,  depending  upon  the  bedding  of  the  limestone. 
Ore  occurred  along  at  least  two  different  bedding  planes.  The 
wall  rock  next  to  the  ore  bodies  is  considerably  altered  and  some 
gouge  was  noted  along  bedding  planes.  Altered  garnet  was  ob- 
served in  the  wall  rock  of  one  stope  but  no  intrusive  rocks  are 
known  underground.  The  ore  is  almost  entirely  oxidized  and  be- 
cause of  the  oxidation  about  50  per  cent  of  the  gold  was  saved  by 
amalgamation. 

C.  W.  Stallings  estimates  the  total  production  of  the  property 
at  $40,000. 

PLACER  DEPOSITS 

The  first  important  placer  deposits  discovered  in  Montana 
were  those  at  Bannack  in  1862.  They  produced  $600,000  within 
the  first  year.  Although  some  of  the  bench  placers  have  been 
worked,  the  most  productive  were  those  in  the  stream  bed  of  Grass- 


57.  Stallings,  C.  W. : Personal  communication. 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


hopper  Creek  or  along  tributary  gulches.  Mr.  Dunn58  estimates  the 
total  placer  production  of  the  Bannack  district  to  be  about  $8,000,- 
000  distributed  as  follows: 


Bannack  Creek  Placers — 6,000,000  yd.  @ $1  per  yd $6,000,000 

Bannack  Gulch  and  Bench  placers — 4,000,000  yd.  @ 30c  per  yd 1,200,000 

Bon  Accord  Placers — 3,000,000  yd.  @ 30c  per  yd 900,000 


Total $8,100,000 


Winchell  estimates  that  Grasshopper  Creek  produced  $3,000,- 
000  in  gold  during  the  ’sixties. 

The  lode  gold  deposits  are  undoubtedly  the  source  of  the  placer 
gold  since  no  valuable  deposits  are  found  in  Grasshopper  Creek 
above  Bannack  and  the  gold  content  decreases  downstream. 


58.  Dunn,  William  : Personal  communication. 


THE  ARGENT  A AREA 


GENERAL  GEOLOGY 

CHARACTER  AND  DISTRIBUTION  OF  THE  ROCKS 

The  prevailing  rocks  in  the  Argenta  area  are  sedimentary. 
Consolidated  sediments  ranging  in  age  from  Algonkian  to  Penn- 
sylvanian are  found  in  the  region,  and  Permian  and  Mesozoic  rocks 
and  Tertiary  “Lake  Beds”  have  been  described  in  the  Melrose  and 
McCarthy  Mountain  areas,  which  are  situated  a few  miles  north- 
east of  Argenta.59  The  unconsolidated  rocks  in  the  Argenta  area 
include  terrace  gravels  and  glacial  moraine. 

The  total  outcrop  of  intrusive  igneous  rocks  aggregates  hardly 
more  than  one  square  mile  and  but  few  isolated  outcrops  of  extru- 
sive rocks  are  exposed  within  the  map  limits.  This  is  in  sharp  con- 
trast with  the  Bannack  area  where  extrusive  rocks  prevail.  Quartz 
monzonite,  granodiorite,  andesite  porphyry,  and  dacite  porphydy 
occur  as  intrusives  and  trachyte  and  rhyolite  are  the  predominating 
extrusive  rocks.  The  distribution  of  the  various  rocks  is  shown  on 
the  geologic  map  comprising  Plate  1. 

ALGONKIAN  SYSTEM 

SPOKANE  FORMATION 

The  rocks  assigned  to  the  Spokane  formation  crop  out  for 
several  miles  along  the  crest  of  an  anticlinal  fold  which  strikes 
about  N.  25°  E.  Only  the  uppermost  part  of  this  formation  is  ex- 
posed and  consists  of  shales,  quartzitic  sandstones  and  at  least 
one  well-defined  conglomerate  bed.  The  shales  are  thin-bedded  and 
fissile  and  characteristically  have  a high  luster  along  the  parting 
planes.  The  color  is  predominantly  dark  red,  but  beds  of  pale 
olive-green  are  abundant.  Dark  or  brick-red  colors  prevail  in  the 
sandstones  which  show  well-preserved  ripple  marks  and  mud  cracks 
(PI.  XII).  On  the  steeper  slopes  the  top  of  the  Spokane  forma- 
tion is  difficult  to  delineate  because  of  the  thick  talus  of  Flathead 
quartzite  and,  in  other  places,  because  of  the  difficulty  in  dis- 
tinguishing the  lower  beds  of  the  Flathead  quartzite  from  similar 
appearing  beds  in  the  Spokane  formation. 

The  rocks  beneath  the  Flathead  quartzite  have  been  correlated 
with  the  Spokane  formation,  described  by  Calkins  in  the  Philips- 
burg  quadrangle,  because  of  the  marked  resemblance  to  them  and 


59.  Richards,  R.  W.  and  Pardee,  J.  T. : U.  S.  Geol.  Sur.  Bull.  780,  pp.  1-32. 


45 


46 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


because  of  their  position  directly  beneath  the  Flathead  quartzite. 
No  estimates  have  been  made  of  the  thickness  of  these  beds  in  the 
Argenta  district  owing  to  the  incomplete  exposures,  but  Calkins 
estimates  the  formation  to  be  over  10,000  feet  thick  in  the  vicinity 
of  Philipsburg.* 

CAMBRIAN  SYSTEM 

Two  lithologically  different  formations  have  been  tentatively 
assigned  to  the  Cambrian  system.  The  lower  member  is  correlated 
with  the  Flathead  quartzite  because  of  its  lithologic  similarity  to 
that  well-defined  horizon  and  because  of  the  stratigraphic  sequence 
of  dark-red  fissile  shales  and  quartzitic  sandstones  beneath  the  vit- 
reous pink  and  white  Flathead  quartzite  in  other  parts  of  south- 
western Montana. 

The  beds  above  the  Flathead  quartzite  are  comprised  princi- 
pally of  gray  sandy  limestone.  They  are  termed  the  Tilden  forma- 
tion in  this  report  and  are  tentatively  assigned  to  the  Cambrian  sys- 
tem. No  angular  discordance  was  noted  between  the  Flathead 
quartzite  and  the  Tilden  limestones,  where  these  beds  were  known 
to  be  in  normal  contact,  although  folding  and  faulting  have  caused 
a marked  apparent  non-conformity  in  several  places.  The  Tilden 
limestone  has  about  the  same  position  in  the  stratigraphic  columi- 
as  the  Gallatin  formation  of  the  Three  Forks  region60  and  the  beds 
embraced  by  the  Silver  Hill,  Hasmark,  and  Red  Lion  formations  of 
the  Philipsburg  quadrangle.61  The  absence  of  shales  at  the  top  of 
the  Flathead  quartzite  and  throughout  the  Tilden  formation  is, 
however,  in  marked  contrast  with  the  Three  Forks  and  Philipsburg 
regions  where  shales  make  up  a considerable  part  of  the  Cambrian 
system. 

FLATHEAD  FORMATION 

The  beds  assigned  to  the  Flathead  formation  are  largely  pink 
to  red  medium-grained  quartzite.  The  darker  colors  predominate 
toward  the  bottom  of  the  formation  and,  in  general,  the  grain  size 
increases.  The  bedding  is  distinct,  the  beds  usually  being  several 
feet  thick.  Some  indurated  conglomerate  beds  occur  interbedded 
with  the  quartzite.  One  well-defined  conglomerate  horizon  is  ex- 
posed near  the  base  of  the  formation  and  another  pebbly  quartzitic 
sandstone,  composed  largely  of  rounded  quartz  grains  from  one  to 
5 millimeters  in  diameter,  occurs  60  feet  below  the  top  of  the  for- 
mation. 

* Emmons,  W.  H.  and  Calkins,  F.  C. : U.  S.  Geol.  Sur.  Prof.  Paper  78,  p.  45,  1913. 

60.  Peale,  A.  C. : U.  S.  Geol.  Sur.  Geol.  Atlas,  Three  Forks  folio  (No.  24). 

61.  Emmons,  W.  H.,  and  Calkins,  F.  C.,  op.  cit. 


MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


Bullerin  6,  Plate  XI 


A.  GLACIAL  MORAINE  AT  THE  MOUTH  OF  RATTLESNAKE 
CREEK  CANYON  IN  SEC.  15. 


B.  STEEPLY  INCLINED  LIMESTONE  BEDS  IN  THE  N.E.%  OF  SEC.  34. 


MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


Bulletin  6,  Plate  XII 


3 4 

1*  purrent  ripple  marks,  characteristically  developed  in  the  quartzitic  sandstone  beds  near  the 
top  ot  the  Spokane  formation.  (1/6  natural  size.) 

2.  Mud  cracks  from  near  the  top  of  the  Spokane  formation.  (1/3  natural  size.) 

3.  Oolitic  limestone  from  near  the  top  of  the  Tilden  formation.  (3/5  natural  size.) 

4.  Black  magnesian  limestone  with  twiglike  bodies  from  base  of  Ermont  formation.  (1/3  natural 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA  47 

The  bottom  limit  of  the  Flathead  formation  could  not  every- 
where be  accurately  fixed  because  of  the  resemblance  of  some  of 
the  lower  beds  to  some  of  the  upper  beds  of  the  Spokane  formation. 
The  top  of  the  formation  is,  however,  very  definite  where  it  is  in 
contact  with  Tilden  limestone.  The  maximum  thickness  of  the 
Flathead  formation  in  the  Argenta  district  is  believed  to  be  about 
500  feet. 

TILDEN  FORMATION 

The  Tilden  formation  which  lies  directly  above  the  Flathead 
quartzite  is  composed  principally  of  gray  to  pinkish-gray  sandy 
limestone.  The  more  sandy  beds  occur  near  the  base.  Several  of 
the  most  important  ore  deposits  of  the  Argenta  region  occur  in 
this  formation.  It  is  best  exposed  northwest  of  the  Ermont  mine 
where  the  following  section  was  measured: 

Section  of  Tilden  formation  in  canyon  northwest  of  Ermont  mine 

Black  thin-bedded  Devonian  limestone 

Feet 


Muddy-colored  sandy  limestone.  Beds  1 to  4 feet  thick.  Oolitic  limestone 

bed,  8 inches  thick,  10  feet  up  from  base 102 

Light-gray  thin-bedded  sandy  limestone.  Weathers  buff  12 

Massive  crystalline  bluish-gray  sandy  limestone  190 

Fine-grained  pinkish-gray  limestone.  Weathers  tan  10 

Gray  sandy  limestone  20 

Thin-bedded  white  siliceous  limestone  12 

Gray  sandy  limestone  with  6 outstanding  beds.  Mostly  massive.  Pebbly 
limestone  at  base  contains  angular  quartz  fragments  mostly  5 milli- 
meters across  75 


421 

Flathead  formation. 

No  fossils  were  found  in  the  Tilden  formation  at  Argenta. 
Trilobite  remains  and  other  fossils  have  been  found,  however,  in 
the  Upper  Cambrian  beds  of  the  Three  Forks  region62  and  a number 
of  fossils  have  been  collected  in  the  Philipsburg  district.63 

A sill  of  dark  green  andesite  porphyry  closely  parallels  the 
contact  between  the  Flathead  quartzite  and  the  Tilden  formation 
for  some  distance  north  of  Rattlesnake  Creek. 

DEVONIAN  SYSTEM 

ERMONT  FORMATION 

The  rocks  assigned  to  the  Devonian  system  include  a series  of 
limestone  beds  about  1,500  feet  thick.  This  formation  is  termed 
the  Ermont  formation  in  this  report  and  correlates  fairly  well  with 
the  Jefferson  formation  of  the  Three  Forks  region64  although  no 
shale  beds  corresponding  in  position  with  the  Three  Forks  shale 
are  present  in  the  Argenta  district.  Mr.  George  H.  Girty  of  the 


62.  Peale,  A.  C. : op.  cit. 

63.  Emmons,  W.  H.  and  Calkins,  F.  C. : op.  cit.,  p.  63. 

64.  Peale,  A.  C. : op.  cit. 


48 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


United  States  Geological  Survey  identified  Devonian  fossils  from 
near  the  top  of  the  formation.  Cup  corals  have  since  been  found 
in  the  basal  beds  just  south  of  the  Coolidge  mine. 

The  color  contrast  between  the  Ermont  beds  and  the  under- 
lying Tilden  beds  clearly  marks  the  base  of  the  Ermont  formation. 
In  addition,  the  basal  beds  contain  twiglike  bodies  that  give  the 
rock  a peculiar  mottled  appearance  (PI.  XII,  4).  The  top  of  the 
Ermont  formation  is  not  definite  but  was  fixed  at  a cherty  horizon 
in  rocks  that  resemble  the  Madison  formation.  Devonian  fossils 
were  found  230  feet  below  this  horizon  and  Madison  fossils  a short 
distance  above  it. 

Section  of  Ermont  formation  in  vicinity  of  Ermont  mine 

Massive  bluish-gray  limestone  with  black  chert  beds 

Feet 


Poor  exposures  but  probably  bluish-gray  limestone.  Devonian  fossils  from 

dense  bluish-gray  limestone  bed  at  base 230 

Poor  outcrop.  Probably  gray  shale  100 

Dense  light-gray  massive  limestone.  Effervesces  readily  with  dilute  acid ....  30 

Sill  of  dark-green  andesite  porphyry  80 

Dark-colored  magnesian  limestone  with  buff-colored  patches  which  may  be 

due  to  alteration  248 

Black  shaly  limestone  beds  similar  to  basal  beds  80 

Sill  of  dark-green  andesite  porphyry  228 

Black  shaly  magnesian  limestone  with  sugary  appearance.  Beds  mostly  less 
than  6 inches  thick.  Bed  2 feet  thick  with  twiglike  bodies  10  feet  from 
base  490 


1,486 

Tilden  formation. 

The  Ermont  beds  strike  about  N.  20°  E.,  and  have  a fairly  con- 
stant dip  of  from  20°  to  25°  southwest  near  the  Ermont  mine.  A 
few  hundred  feet  eastward  from  the  top  of  the  section,  however, 
there  is  considerable  minor  folding. 

CARBONIFEROUS  SYSTEM 

MISSISSIPPIAN  SERIES 

Mississippian  rocks  are  the  most  widespread  of  the  consolidated 
formations  in  the  Argenta  area.  Fossils  indicate  the  presence  of 
both  Madison  and  Brazer  beds,  but  these  have  not  been  differen- 
tiated. The  Madison  formation  is  made  up  largely  of  massive  bluish- 
gray  limestone  but  black  chert  becomes  abundant  toward  the  top 
of  the  formation.  Fossils  were  found  throughout  but  are  most 
abundant  in  the  upper  horizons.  The  most  common  organic  remains 
are  white  cylindrical  crinoid  stems.  Some  beds  appear  to  be  made 
up  almost  entirely  of  them.  Cup  corals  are  the  next  in  abundance. 
They  are  shaped  like  a cornucopia  and  in  cross  section  the  vertical 
partitions  resemble  somewhat  the  spokes  of  a wheel.  Other  fossils 
occur  in  less  abundance.  The  Brazer  formation  does  not  differ 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA 


49 


greatly  in  appearance  from  the  Madison  beds.  It  likewise  includes 
numerous  fossils  and,  like  the  Madison,  contains  beds  made  up 
almost  entirely  of  crinoid  stems. 

No  outcrop  in  the  Argenta  vicinity  is  suitable  for  the  measure- 
ment of  a section  across  the  Mississippian  beds,  principally  because 
of  the  faulting  and  folding.  Faulting  has  caused  an  apparent  thick- 
ening, particularly  in  the  westerly  part  of  the  area.  About  1,300 
feet  of  Madison  beds  are  exposed  in  the  Melrose  region65  and  about 
1,200  feet  were  measur2d  in  the  Bannack  district. 

PENNSYLVANIAN  SERIES 

The  Pennsylvanian  series  embraces  two  distinct  rock  types  in 
the  Argenta  district,  a lower  limestone  formation  and  the  quartz- 
ite and  sandstone  which  overlie  it.  The  lower  Pennsylvania  beds 
(Wells)  resemble  the  Upper  Mississippian  (Brazer)  beds  in  litho- 
logic appearance  and  were  not  mapped  as  separate  units.  Fossil 
collections,  however,  indicate  that  both  formations  are  present. 
Wells  fossils  were  collected  about  300  feet  stratigraphically  beneath 
the  quartzite  beds. 

The  Quadrant  quartzite,  which  overlies  the  Wells  formation, 
is  exposed  in  several  places  within  the  map  limits.  The  largest  out- 
crops are  in  secs.  15  and  34  and  a smaller  remnant  occupies  a syn- 
clinal trough  in  sec.  20.  Several  other  small  patches  have  been 
mapped.  Quadrant  quartzite  crops  out  continuously  from  the  north- 
ern end  of  the  Bannack  district  into  the  Argenta  area  and  is  every- 
where similar  in  character.  The  lower  beds  are  composed  largely  of 
white  and  pink  vitreous  quartzite  which  changes  to  sandstone 
toward  the  top  of  the  formation.  The  upper  part  of  the  forma- 
tion has  been  removed  by  erosion  but  the  remaining  beds  are  over 
500  feet  in  thickness. 

TERTIARY  GRAVELS 

The  older  gravel  deposits  of  the  Argenta  district  have  been 
designated  as  “Upper  Bench  Gravels”  and  “Lower  Bench  Gravels” 
because  of  their  relative  positions.  The  “Upper  Bench  Gravels’’ 
reach  an  elevation  of  6;800  feet.  The  lower  terrace  has  been  cut 
into  the  upper  gravels  and  is  best  represented  by  the  flat  upon 
which  the  town  of  Argenta  is  built.  Still  more  recently,  Rattle- 
snake Creek  has  cut  a deep  channel  into  the  lower  bench  and  is  now 
actively  engaged  in  the  process  of  degradation. 

The  formations  underlying  the  terraces  are  not  well  exposed, 


65.  Richards,  R.  W.  and  Pardee,  J.  T. : op.  cit. 


50 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


although  Rattlesnake  Creek  has  cut  through  beds  of  sandstone 
and  gravel  east  of  Argenta.  The  surface  of  the  terraces  is  nearly 
everywhere  covered  by  a mantle  of  coarse,  unconsolidated  gravel. 
This  loose  material  may  have  come  from  the  weathering  of  the 
underlying  beds  or  it  may  have  been  deposited  by  more  recent 
streams.  The  superficial  material  is  composed  largely  of  rounded 
quartzite  pebbles  and  boulders  ranging  from  less  than  an  inch  to 
over  a foot  in  size.  They  are  mixed  with  some  sand  and  black  chert. 
The  quartzite  pebbles  are  predominantly  pink  or  white  and  many 
show  bedding  plainly.  Fossil  remains  found  by  Douglas66  in  beds 
similar  to  the  terrace  deposits  indicate  an  Oligocene  age. 

QUATERNARY  DEPOSITS 

The  Quaternary  deposits  are  represented  by  recent  stream 
gravels  and  glacial  moraines.  Rattlesnake  Creek  is  depositing 
gravels  in  its  present  channel  and,  part  of  the  superficial  gravel 
covering  the  terraces  may  have  been  deposits  by  recent  streams. 

GLACIAL  MORAINE 

A well-developed  glacial  moraine  has  been  deposited  by  a valley 
glacier  at  the  mouth  of  the  narrow  canyon  of  Rattlesnake  Creek 
in  sec.  15  (PL  XII,  1).  Erosion  has  also  left  a small  remnant  of  a 
moraine  on  a bench  in  the  SE.*4  of  sec.  15.  These  moraines  repre- 
sent the  lower  limits  of  the  mountain  glaciers  that  have  moved 
down  the  present  canyons.  The  boulders  in  the  moraines  consist 
mainly  of  granite  or  quartz  monzonite  with  lesser  amounts  of 
quartzite  and  limestone.  A moraine  has  been  utilized  to  form  a 
reservoir  about  a half-mile  north  of  the  map  limits  where  Rattle- 
snake Creek  cuts  a narrow  canyon  through  a glacial  deposit. 

INTRUSIVE  IGNEOUS  ROCKS 

GENERAL  FEATURES 

The  intrusive  rocks  of  the  Argenta  district  include  quartz  mon- 
zonite, granodiorite,  andesite  porphyry  and  dacite  porphyry.  The 
former  two  have  been  intruded  into  older  rocks  as  large  irregu- 
lar bodies  whereas  the  latter  two  occur  as  sills  and  dikes.  The 
quartz  monzonite  and  granodiorite  rocks,  like  the  intrusive  rocks 
of  the  Bannack  district,  are,  no  doubt,  genetically  related  to  the 
“Boulder  batholith”67  and  probably  represent  the  high  points  or 
cupolas  of  a much  larger  body  which  erosion  has  not  yet  exposed 
to  view.  The  most  recent  work  indicates  that  the  Boulder  batholith 


66.  Douglas,  Earl : Carnegie  Mus.  Annals,  vol.  4,  pp.  278-281,  1908. 

67.  Billingsley,  Paul : Trans.  A.  I.  M.  E.,  vol.  51,  pp.  31-56. 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA 


51 


is  of  late  Cretaceous  or  early  Eocene  age.68  The  andesite  porphyry 
dikes  cut  the  larger  intrusive  masses  so  that  they  were  evidently 
intruded  at  least  after  the  outer  portions  of  the  latter  had  cooled. 

QUARTZ  MONZONITE 

Two  exposures  of  quartz  monzonite  occur  in  the  Argenta  region. 
One  mass  crops  out  west  of  the  town  of  Argenta  and  another  is  ex- 
posed near  the  southeast  corner  of  sec.  17.  Both  outcrops  resemble 
each  other  closely  in  lithologic  appearance. 

PETROGRAPHY 

The  rock  is  gray  and  medium  to  coarse-grained,  but  the  light- 
colored  minerals  predominate  over  the  dark  ones.  Quartz  is  clearly 
discernible  in  the  hand  specimens.  The  microscope  shows  the  rock 
to  be  made  up  largely  of  light-colored  minerals  with  biotite,  horn- 
blende and  magnetite  constituting  the  bulk  of  the  dark  minerals. 
The  plagioclase  crystals  are  lath-shaped  and  vary  from  0.2  to  over 
2 millimeters  in  length  and  average  about  0.5  by  1.0  millimeters 
in  cross  sections.  They  show  very  little  alteration.  Extinction 
angles  show  the  plagioclase  to  be  andesine  (AbG-An4)  in  composition. 
It  constitutes  about  45  per  cent  of  the  rock.  Orthoclase  is  present 
in  smaller  amounts,  estimated  at  30  per  cent.  It  occurs  as  tabular 
crystals  or  irregular  masses  and  is  characteristically  zoned.  Some 
of  it  is  partly  altered  to  sericite.  Quartz  is  present  as  interstitial 
material  and  makes  up  about  15  per  cent  of  the  rock.  The  ratio 
of  biotite  to  hornblende  varies  from  place  to  place.  In  the  sections 
studied  the  biotite  was  estimated  at  7 per  cent  and  the  hornblende 
at  about  3 per  cent.  The  biotite  commonly  contains  feldspars  as 
poikolitic  inclusions.  Magnetite,  titanite  and  zircon  occur  as  ac- 
cessory minerals.  Magnetite  comprises  about  1 per  cent  of  the 
rock,  and  apatite  and  zircon  together  constitute  a still  smaller 
amount. 

GRANODIORITE 

Two  outcrops  of  granodiorite  are  exposed  near  the  Dexter  mine 
in  sec.  17.  They  are  separated  by  a narrow  belt  of  altered  limestone 
and  are,  no  doubt,  a continuous  body  beneath  it.  The  exposures  ag- 
gregate about  a quarter  of  a square  mile.  No  direct  relationship 
was  found  between  the  granodiorite  and  the  quartz  monzonite.  It 
seems  probable,  however,  that  they  have  had  a common  origin  and 
that  the  latter  represents  a stage  of  deeper  erosion.  Some  assimila- 
tion near  the  top  of  the  cupolas  may  account  for  the  lower  silica 
content  in  the  granodiorite. 

68.  Knopf,  Adolph  : U.  S.  Geol.  Sur.  Bull.  527,  p.  34,  1913. 

Stone,  R.  W.  and  Calvert,  W.  R.  : Ec.  Geol.,  vol.  5,  pp.  551-557,  662-669,  744-764,  1910. 


52 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


PETROGRAPHY 

The  granodiorite  is  a medium  to  fine-grained  rock  in  which 
the  light  and  dark  minerals  appear  to  be  in  about  equal  proportions. 
No  quartz  can  be  observed  in  the  hand  specimens.  Thin  sections 
show  the  rock  to  be  composed  principally  of  plagioclase,  orthoclase 
and  hornblende  with  little  or  no  biotite.  The  boundaries  of  the 
mineral  grains  tend  to  coalesce,  especially  in  the  dark  finer-grained 
phases.  This  same  characteristic  is  marked  in  the  quartz  monzonite 
near  the  contacts  with  limestone.  The  lath-shaped  plagioclase  crys- 
tals have  an  average  cross  section  of  0.5  by  0.2  millimeters  and  a 
maximum  extinction  angle  of  about  25  degrees  which  would  classify 
it  as  andesine  (Ab6-An4).  The  plagioclase  is  decidedly  zoned  and 
shows  considerable  alteration,  particularly  along  fractures.  An- 
desine constitutes  about  50  per  cent  of  the  rock.  Orthoclase  is 
present  as  interstitial  material  and  as  rounded  grains,  some  of 
which  are  over  2 millimeters  across.  The  larger  orthoclase  crystals 
show  zoning  but  it  is  not  as  marked  as  in  the  quartz  monzonite. 
The  amount  present  is  estimated  at  20  per  cent.  Green  hornblende 
makes  up  about  25  per  cent  of  the  rock.  It  is  variable  in  size  and 
shape  but  averages  about  1.3  by  0.4  millimeters  in  cross  section. 
Basal  sections  show  very  perfect  amphibole  cleavage  (PI.  XIII,  2). 
The  hornblende  commonly  includes  grains  of  magnetite  and  feld- 
spar and  some  of  it  is  partly  altered  to  chlorite  and  limonite.  In 
general,  however,  the  hornblende  is  fairly  free  from  alteration. 
Quartz  makes  up  less  than  5 per  cent  of  the  rock  and  occurs  as 
interstitial  grains.  Magnetite  constitutes  about  3 per  cent  and 
titanite  and  zircon  less  than  1 per  cent  of  the  rock. 

ANDESITE  PORPHYRY 

The  andesite  porphyry  intrusions  in  the  Argenta  district  occur 
chiefly  as  sills  although  some  andesite  porphyry  was  found  to  occur 
as  dikes.  The  largest  outcrops  of  andesite  porphyry  are  exposed 
near  the  Ermont  mine,  in  secs.  26  and  35.  The  Ermont  intrusives 
have  the  general  characteristics  of  sills  and  in  places  they  clearly 
cut  across  the  bedding  planes  of  the  limestone.  It  is  possible  that 
the  sills  north  of  Rattlesnake  Creek,  in  sec.  24,  are  the  northward 
extensions  of  the  intrusives  near  the  Ermont  mine.  They  are  similar 
in  appearance  although,  in  general,  the  Rattlesnake  sills  are  more 
intensely  altered.  A.  H.  French  found  andesite  porphyry  in  a 
tunnel  on  the  Tuscarora  property.  Thin  sections  show  some  of  the 
dikes  across  the  creek  from  Argenta  in  sec.  29,  to  be  andesite  por- 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA 


53 


phyry,  although  most  of  these  dikes  usually  contain  considerable 
quartz. 

PETROGRAPHY 

Two  types  of  andesite  porphyry  prevail  in  the  Argenta  region. 
One  type  is  a dense  grayish-green  rock  that  does  not  show  marked 
porphyrytic  characteristics  in  hand  specimens  and  the  other  is  a 
grayish-green  rock  with  very  evident  lath-shaped  phenocrysts  of 
black  augite  in  a dense  groundmass.  No  doubt,  both  have  come 
from  a common  source. 

The  microscope  shows  the  former  to  be  comprised  of  a micro- 
crystalline groundmass  with  phenocrysts  of  altered  plagioclase  and 
orthoclase  and  alteration  remnants  of  ferromagnesian  mineral  (PL 
XIII,  3).  Magnetite  grains  are  disseminated  throughout  the  entire 
rock.  Extinction  angles  indicate  that  the  plagioclase  has  the  com- 
position of  andesine.  Most  of  it  is  wholly  or  partly  altered  to  cal- 
cite  and  sericite  and  the  orthoclase  largely  to  sericite.  Only  the 
alteration  remnants  of  the  ferromagnesian  minerals  remain.  They 
consist  chiefly  of  chlorite,  talc,  and  limonite.  Patches  of  calcite 
occur  throughout  the  rock.  Quite  a little  secondary  silica  is  present 
in  the  groundmass.  Little  primary  quartz  was  noted.  Although 
alteration  makes  the  classification  of  the  rock  uncertain,  evidence 
indicates  that  it  is  an  andesite  porphyry. 

The  andesite  porphyry  with  the  abundant  augite  phenocrysts 
is  not  so  highly  altered  as  the  dense  rock.  Feldspar  and  augite 
phenocrysts  occur  in  a microcrystalline  groundmass  composed  large- 
ly of  small  lath-shaped  feldspars  and  constitute  about  one-third  of 
the  rock.  The  plagioclase  phenocrysts  range  in  length  from  about 
0.5  to  1.0  millimeters  and  the  average  augite  crystal  is  about  1.0 
millimeters  long  by  0.3  millimeters  wide.'  Occasional  augite  pheno- 
crysts are  over*  1 centimeter  in  length.  The  plagioclase  feldspars 
have  the  composition  of  andesine  and  are  considerably  altered  but 
many  still  retain  the  twinning  striae.  Orthoclase  phenocrysts  are 
less  abundant  than  andesine.  The  augite  is  light-green  in  ordinary 
light  and  most  of  the  crystals  are  twinned.  Calcite  occurs  along 
fractures  but,  in  general,  the  augite  is  only  slightly  altered.  It 
commonly  includes  magnetite  and  irregular  patches  of  groundmass 
material.  Augite  constitutes  about  50  per  cent  of  the  phenocrysts. 
Magnetite  constitutes  about  2 per  cent  of  the  rock.  Little  or  no 
quartz  was  noted  in  the  thin  sections.  This  rock  is  classified  as  an 
augite-andesite  porphyry. 

DACITE  PORPHYRY 

A number  of  dikes  cut  the  quartz  monzonite  west  of  Argenta. 


54 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


They  are  similar  in  appearance  to  andesite  porphyry,  some  con- 
tain considerable  quartz.  They  range  in  color  from  almost  white  to 
grayish-green,  depending  upon  the  degree  of  alteration.  All  con- 
tain some  quartz  but  only  those  containing  it  in  appreciable  amounts 
are  termed  dacite  porphyries.  All  are  probably  phases  of  the  same 
intrusive. 

PETROGRAPHY 

The  dacite  porphyry  is  almost  white  to  grayish-green  in  color 
and  is  noticeably  porphyritic.  Phenocrysts  of  bleached  feldspar  and 
glassy  quartz  are  clearly  visible  in  the  hand  specimens.  Small 
patches  of  limonite  give  the  rock  a spotted  appearance. 

Thin  sections  show  the  rock  to  contain  phenocrysts  of  feldspar, 
augite  and  quartz  in  a felted  groundmass.  The  phenocrysts  make 
up  about  one-third  of  the  rock.  Except  for  the  presence  of  more 
quartz,  the  dacite  porphyry  does  not  differ  greatly  in  appearance 
from  the  andesite  porphyry.  Both  phenocrysts  and  groundmass 
are  considerably  altered  but  the  twinning  striae  are  still  visible 
on  the  plagioclase  crystals.  All  of  the  quartz  phenocrysts  observed 
were  rounded  in  outline  and  most  of  them  showed  marked  embay- 
ments  (PI.  XIII,  4). 

RHYOLITE  PORPHYRY 

A highly  altered  igneous  rock  occurs  across  the  creek  from 
Argenta.  It  is  a white  porous  rock  with  numerous  casts,  some  lined 
with  limonite.  The  rock  has  a sugary  appearance  and  is  character- 
ized by  a high  porosity.  The  square  shape  of  the  cavities  and  the 
fact  that  many  are  entirely  free  from  limonite  indicates  that  they 
may  once  have  been  occupied  by  pyrite.  This  rock  is  said  to  con- 
tain gold  in  small  amounts.  It  is  tentatively  classified  as  an  altered 
rhyolite  porphyry  because  of  the  light  color  and  fhe  presence  of 
quartz  phenocrysts. 

CONTACT  METAMORPHIC  EFFECTS 

The  most  intense  metamorphic  effects  have  been  observed  in 
the  limestone  beds  near  their  contact  with  granodiorite  and  quartz 
monzonite.  Granodiorite  has  intruded  shale  beds  near  the  Dexter 
mine  but  the  contact  effects  are  much  less  noticeable  than  in  the 
limestones  near  by.  The  shales  have  been  silicified  and  are  rust- 
brown  in  color — apparently  due  in  part  to  the  weathering  of  in- 
cluded iron-bearing  minerals. 

The  most  common  effects  in  the  limestones  are  recrystalliza- 
tion and  garnetization.  Vesuvianite,  epidote  and  tremolite  were  ob- 
served in  association  with  the  garnet  but  epidote  is  much  less  com- 


MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


Bulletin  6,  Plate  XIII 


PHOTOMICROGRAPHS  OF  INTRUSIVE  ROCKS  FROM  THE  ARGENTA  DISTRICT 

1.  Quartz  monzonite  from  N.E.%  of  sec.  20.  Quartz  (white),  biotite  (b),  andesine  (a).  Polarized 
light.  Magnification  23  times. 

2.  Diorite  from  N.W.%  of  sec.  17.  Andesine  (a),  hornblende  with  well-developed  amphibole 
cleavage  (h),  black  mineral  in  center  of  hornblende  is  magnetite,  irregular  black  patch  is 
hornblende  at  extinction.  Polarized  light.  Magnification  28  times. 

3.  Andesite  porphyry  from  the  larger  intrusive  body  in  N.E.1/]  of  sec.  35.  Shows  partly  altered 
andesine  crystals  in  silicified  microcrystalline  groundmass.  Polarized  light.  Magnification  28 
times. 

4.  Dacite  porphyry  dike  from  N.W.%  of  sec.  29.  Shows  microcrystalline  groundmass  and  partly 
resorbed  quartz  crystal  (white).  Ordinary  light.  Magnification  14  times. 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA 


mon  than  in  the  Bannack  district.  The  most  widespread  contact 
metamorphic  product  is  a dense  greenish-yellow  greasy-appearing 
rock.  It  is  well-developed  around  the  northern  border  of  the  quartz 
monzonite  mass  across  the  creek  from  Argenta.  Thin  sections  showT 
this  rock  to  be  composed  largely  of  isotropic  garnet.  In  addition  to 
the  garnet,  the  ore  bodies  around  the  contacts  afford  further  evi- 
dence of  introduced  material. 

The  granodiorite  and  quartz  monzonite  also  show  a difference 
near  the  limestone  contacts.  They  are  darker-colored  and  notice- 
ably finer-grained.  Thin  sections  show  a lower  quartz  content  and 
a marked  tendency  to  coalescence  of  the  feldspar  grains.  Analyses 
of  the  intrusive  rocks  near  the  limestone  contacts  in  the  Bannack 
district  show  an  increase  in  lime,  magnesia  and  iron.69 

The  contact  metamorphic  effects  of  the  andesite  porphyry  are 
much  less  intense  than  those  of  the  granodiorite  and  quartz  mon- 
zonite. Silicification  of  the  limestone  beds  is  the  most  evident  re- 
sult. The  andesite  porphyry  itself  is  denser  in  appearance  near 
the  contact. 

EXTRUSIVE  IGNEOUS  ROCKS 

RHYOLITE  PORPHYRY 

A patch  of  dense  light-gray  porphyritic  rock  occurs  near  the 
southeast  corner  of  sec.  36.  It  contains  in  a highly  altered  ground- 
mass,  many  phenocrysts  of  angular  quartz  and  numerous  patches  of 
calcite,  which  may  be  the  decomposition  product  of  feldspar.  Be- 
cause of  the  abundant  quartz  and  light  color  this  rock  is  classified 
as  a rhyolite  porphyry. 

TRACHYTE  PORPHYRY 

A dense  gray  rock  with  well-developed  phenocrysts  of  ortho- 
clase  occurs  on  top  of  the  Quadrant  quartzite  in  the  southeast  cor- 
ner of  sec.  34  and  a similar  appearing  rock  was  found  on  the  top 
of  the  ridge  in  the  NE.l/4  of  sec.  22  and  another  outcrop  on  the 
high  ridge  near  the  center  of  sec.  14. 

The  microscope  shows  the  rock  to  be  composed  of  orthoclase 
phenocrysts,  aggregating  about  25  per  cent  of  the  rock,  in  a dense, 
partly  silicified  groundmass.  Very  little  primary  quartz  was  noted. 
The  orthoclase  phenocrysts  are  slightly  altered  to  sericite. 


69.  Idem,  p.  16. 


56 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


DEFORMATION 

GENERAL  FEATURES 

The  structure  of  the  Argenta  region  is  complex  and  only  the 
broader  features  are  shown  on  the  map  and  sections.  The  sedi- 
mentary beds  have  been  compressed  into  a series  of  folds  with 
a northerly  trend.  In  places  these  folds  have  been  broken  and 
displaced  along  fault  surfaces.  Two  distinct  types  of  faults  have 
been  developed.  East-west  compressional  forces  have  caused  older 
rocks  to  be  shoved  over  younger  rocks  along  thrust  faults,  and 
later,  other  forces  resulted  in  the  further  breaking  of  the  forma- 
tions by  normal  faults.  The  faults  are  made  evident  by  the  cutting 
out  of  beds,  the  severe  folding  and  tilting  that  interrupt  their 
continuity  and  in  places  by  the  direct  observation  of  the  fault  sur- 
faces. 

The  deformation  in  the  Argenta  district  is  merely  the  local 
expression  of  a great  system  of  folding  and  overthrust  faulting 
which  is  known  to  extend  from  Canada  into  Utah.  It  has  been  de 
scribed  in  the  Philipsburg  district  by  Calkins,70  by  Richards  and 
Pardee71  in  the  Melrose  district,  by  Richards  and  Mansfield72  in 
Idaho,  and  by  Willis73  in  northern  Montana,  and  in  the  Bannack 
area  elsewhere  in  this  report. 

PRINCIPAL  FOLDS  AND  FAULTS 

The  most  prominent  structural  feature  is  the  broad  anticlinal 
fold  which  occupies  much  of  the  Argenta  area  and  extends  to  the 
north  beyond  the  limits  of  the  map.  It  is  around  this  fold  that 
the  best  records  of  the  sedimentary  rocks  are  available.  The  fold 
is  not  intact  but  has  been  broken  by  faults.  A smaller  anticlinal 
fold  separates  two  small  synclines  in  the  eastern  part  of  the  district. 
North  of  Argenta  the  eastern  syncline  is  occupied  by  Quadrant 
quartzite  which  erosion  has  not  entirely  removed.  Another  less 
conspicuous  fold  is  developed  near  the  western  border  of  the  mapped 
area.  Minor  folds  are  abundant.  Intense  minor  folding  can  be  ob- 
served from  the  road  just  northeast  of  the  southwest  corner  of 
sec.  19. 

Thrust  faults  account  for  much  of  the  deformation.  One  has 
shoved  Madison  beds  over  Quadrant  quartzite  in  the  western  part 
of  the  area  and  another  fault  of  less  displacement  has  moved  Spo- 
kane beds  into  contact  with  Tilden  limestone  in  the  vicinity  of 

70.  Emmons,  W.  H.  and  Calkins,  F.  C.  : U.  S.  Geol.  Sur.  Prof.  Paper  78,  1913. 

71.  Richards,  R.  W.  and  Pardee,  J.  T.  : U.  S.  Geol.  Sur.  Bull.  780,  1925. 

72.  Richards,  R.  W.  and  Mansfield,  G.  R. : U.  S.  Geol.  Sur.  Bull.  577,  1914. 

73.  Willis,  Bailey:  Geol.  Soc.  of  America,  Bull.  vol.  13,  pp.  305-52,  1902. 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA 


57 


the  Midnight  mine.  A major  normal  fault  trending  north  and  south 
with  several  splits  has  dropped  upper  Madison  beds  into  contact 
with  Ermont  limestones  in  the  western  part  of  the  area.  Numer- 
ous small  normal  faults  were  noted  in  many  places  but  because  of 
the  scale  these  are  not  shown  on  the  areal  map. 

Folding  evidently  took  place  before  intrusion  of  the  igneous 
rocks  in  the  Argenta  district  because  they  can  be  observed  cutting 
across  the  folds.  As  the  late  Tertiary  lavas  have  been  folded  and 
faulted  also,  it  is  evident  that  there  were  at  least  two  periods  of 
deformation  or  else  the  process  was  continuous.  The  most  intense 
folding  probably  occurred  in  the  Cretaceous  period.  Billingsley74 
has  placed  the  beginning  of  the  deformation  in  western  Montana 
in  the  late  Cretaceous. 


ORE  DEPOSITS 

HISTORICAL  SKETCH  OF  MINING 

After  most  of  the  available  claims  had  been  staked  in  the 
Bannack  district  numerous  prospectors  spread  over  the  nearby 
hills  in  search  of  new  “diggings”.  Some  placer  ground  was  dis- 
covered near  Argenta  but  it  was  not  until  the  spring  of  1865  that 
A.  M.  Esler  of  Bannack  discovered  the  Legal  Tender,  the  first 
important  mine  in  the  Argenta  district.75  The  ore  was  rich  but  as 
the  shipment  charges  to  Swansea,  Wales,  the  nearest  smelter,  con- 
sumed most  of  the  profit,  Mr.  Esler  decided  that  same  year  to 
build  a smelter,  the  first  in  the  State  of  Montana.  It  had  a capacity 
of  six  tons  per  day.76  Subsequently  a refining  furnace  or  cupel  was 
added  because  the  freight  charges  prohibited  the  shipment  of  the 
lead.  Mr.  Esler  sold  his  smelter  to  S.  H.  Bohm  and  Company  of 
Helena,  Montana,  who  operated  it  as  a custom  plant.  They  also 
acquired  the  Ferdinand  and  Brownell  mines.  A second  smelter  was 
built  in  1866  by  Tootle  Leach  & Co.  of  St.  Louis,  for  the  treatment 
of  the  Tuscarora  ore.  This  smelter  was  purchased  by  W.  A.  Clark, 
in  1869.  The  third  smelter  was  built  in  1867  by  the  St.  Louis  & 
Montana  Mining  Co.,  principally  for  the  treatment  of  the  Iron  Moun, 
tain  ore.  It  was  afterward  owned  and  operated  by  E.  S.  Ball,  who 
in  turn  sold  to  the  P.  J.  Kelly  Placer,  Quartz  & Reduction  & Smelt- 
ing Co.  A fourth  furnace,  constructed  of  inferior  fire-brick,  melted 
upon  the  first  heating. 

For  a number  of  years  the  various  smelters  continued  to  treat 

74.  Billingsley,  Paul  : Trans.  A.  I.  M.  E.,  vol.  51,  pp.  31-56,  1915. 

75.  French,  G.  W.  : Mining  Truth,  Spokane,  Wash.,  p.  23,  April  3,  1930. 

76.  Browne,  J.  Ross,  Mineral  Resources  of  the  United  States  for  1866. 

Montana,  pp.  310,  1868. 


58 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


ore  mainly  from  Argenta,  though  some  ores  from  the  Blue  Wing 
and  other  district  were  treated  also.  In  later  years  the  ores  have 
been  hauled  to  the  railroad  at  Dillon  and  shipped  to  various  smelters 
and  mills  in  Montana  and  Utah. 

Like  those  in  the  Bannack  district,  the  mines  at  Argenta  have 
been  worked  at  intervals  in  recent  years.  In  1928  the  Ferdinand, 
Iron  Mountain  and  Brownell  shipped  considerable  ore,  although 
little  activity  was  evident  during  the  summer  of  1929.  In  general, 
the  activity  follows  the  trend  of  the  metal  market. 

Lead  and  silver  are  the  most  important  metals  produced  in 
the  Argenta  district.  The  gold  production  is  next  in  importance 
and  considerable  copper  and  zinc  have  been  mined.  Of  30  or  more 
mines  and  prospects  in  the  district,  15  account  for  nearly  all  the 
production.  Seven  account  for  most  of  the  lead  and  silver  pro- 
duced, four  for  most  of  the  gold,  two  for  much  of  the  copper  and 
one  for  most  of  the  zinc. 

Practically  all  the  production  has  come  from  the  lode  mines. 
Some  placers  were  worked  but  no  figures  are  available  as  to  the 
amount  of  gold  produced.  Many  of  the  lode  mines  were  operated 
before  statistics  were  recorded  so  that  the  production  figures  for 
a number  of  them  are  merely  estimates  based  largely  upon  the 
size  of  the  underground  excavations  and  the  grade  of  the  ore. 
Messrs.  A.  H.  and  George  French,  who  are  familiar  with  the  history 
of  most  of  the  mines,  have  contributed  much  information.  The 
total  production  of  the  Argenta  district  is  estimated  at  $1,500,000. 

CLASSIFICATION  OF  THE  ORE  DEPOSITS 

Ore  deposits  are  commonly  classified  for  descriptive  purposes 
according  to  their  metal  content;  according  to  the  enclosing  wall 
rock ; according  to  their  genesis ; or  according  to  the  forms  of  the 
ore  bodies.  A combination  of  the  latter  three  is  used  in  the  follow- 
ing description  and  comparison  of  the  deposits: 

1.  Pipe-like  ore  bodies  in  limestone: 

Tuscarora 

Gov.  Tilden 
Florida 

2.  Tabular  ore  shoots  along  bedding  planes  in  limestone: 

Legal  Tender 

Spanish  mine 
Fraction  (in  part) 

Wooley  “ “ 

Coolidge  “ “ 

3.  Tabular  ore  shoots  along  fissures  in  limestone: 

Brownell 

Mauldin 

Anaconda 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA  59 

Coolidge  (in  part) 

Goldsmith  “ “ 

Fraction  “ “ 

Wooley  “ “ 

4.  Contact  deposits  in  limestone: 

Iron  Mountain 

Argenta  Mining  Company 
Ermont 

5.  Deposits  along  fissures  or  shear  zones  in  quartzite: 

Carbonate 

Ground-hog 
Goldfinch  (in  part) 

Lookout 

6.  Deposits  along  fissures  in  shale: 

Golden  Era 

Rena 

Midnight 

Goldfinch  (in  part) 

Dexter 

Gladstone 

7.  Ore  shoots  along  veins  and  shear  zones  in  quartz  monzonite: 
Ferdinand 

Jack  Rabbit 
Copper  Bell 
Bella 


PIPE-LIKE  ORE  BODIES  IN  LIMESTONE 

Pipe-like  ore  bodies  in  limestone  have  been  the  source  of  much 
of  the  lead  and  silver  produced  in  the  Argenta  district.  The  de- 
posits of  this  type  usually  consist  of  pipe-like  shoots  which  com- 
monly split  and  rejoin  as  they  are  followed  along  the  dip  of  the 
limestone  beds.  The  mineral-bearing  solutions,  no  doubt,  followed 
lines  or  zones  of  weakness,  but  control  fissures  are  usually  not 
obvious.  The  shoots  are  usually  continuous  except  where  they  are 
interrupted  by  faults.  Prescott77  has  clearly  described  the  under- 
lying principles  of  deposits  of  this  type  in  Mexico.  In  prospecting 
this  type  of  deposit  the  ore  should  be  followed  as  closely  as  possible 
for  even  with  a thorough  knowledge  of  the  stratigraphy  and  the 
principles  involved  it  is  extremely  hazardous  to  run  long  explora- 
tion tunnels  for  the  intersection  of  the  ore  shoots. 

TUSCARORA  MINING  AND  SMELTING  CO.  PROPERTY 

The  Tuscarora  Mining  and  Smelting  Co.,  property  includes  two 
of  the  most  important  mines  in  the  Argenta  district.  The  group 
embraces  the  Tuscarora,  Gov.  Tilden,  Florida,  Wooley,  Fraction, 
Fraction  Placer,  Reform,  Burleigh,  and  Spring  claims,  all  in  sec.  18. 
Most  of  the  work  and  production  has  been  confined  to  the  first  two. 
The  B.  F.  White  estate  of  Dillon,  Montana,  owns  one-half  interest 


77.  Prescott,  Basil : Eng.  and  Min.  Jour.  vol.  122,  pp.  246-253,  289-296,  1926. 


60 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


and  the  Anaconda  Copper  Mining  Co.,  one-half  interest  in  the  Gov. 
Tilden,  Florida,  Wooley,  Fraction,  Fraction  Placer,  Reform,  Bur- 
leigh, and  Spring  claims.  The  Anaconda  Copper  Mining  Co.,  has 
the  entire  ownership  in  the  Tuscarora. 

The  Tuscarora  was  discovered  in  1865,  by  Amede  Bessette  and 
Wash  Stapleton.  The  Gov.  Tilden  was  discovered  a short  time  later. 
W.  G.  Gallagher  and  LaFayette  Scott  acquired  the  mine  from  the 
locators  and  extracted  considerable  ore  in  the  late  ’seventies.  W.  A. 
Clark  bought  LaFayette  Scott’s  interest  in  the  early  ’eighties  and 
continued  to  run  the  smelter  partly  with  ore  from  the  Tuscarora 
and  partly  with  custom  ores.  During  this  time  the  incline  was  run 
from  the  Tuscarora  into  the  Florida,  where  a fault  is  said  to  have 
terminated  the  ore.  Clark  shipped  several  cars  of  ore  from  the 
Tuscarora  and  the  Gov.  Tilden  in  1895-96,  following  which  Gallagher 
made  several  shipments.  Frank  Benton  leased  the  property  in 
1898-99,  and  shipped  195  tons  of  ore  from  a pipe-like  shoot  in  the 
Gov.  Tilden  which  ran  south  and  west  along  the  bedding  and  then 
turned  and  crossed  over  the  incline.  None  of  his  workings  are  now 
open.  During  the  period  from  1914-21,  Messrs.  A.  H.  French  and 
W.  G.  Graeter  shipped  ore  and  some  concentrates  from  the  Gov. 
Tilden,  which  had  a gross  value  of  $30,000.  The  concentrates  were 
made  by  jigging  the  dumps.  With  the  exception  of  two  cars  washed 
by  McKay  and  Ross  these  are  the  only  concentrates  that  are  known 
to  have  been  shipped  from  the  property.  The  size  of  the  excava- 
tions indicate  that  the  Tuscarora  and  Florida  produced  from  5.000 
to  7,000  tons  of  ore  and  the  Gov.  Tilden  from  2,000  to  3,000  tons. 
These  figures  are  in  accordance  with  estimates  made  by  A.  H. 
French.78 

Most  of  the  ore  from  the  Tuscarora  claim  was  extracted  from 
open  cuts  although  considerable  ore  is  said  to  have  been  taken  out 
of  the  incline  extending  from  the  Florida  shaft  which  ran  directly 
beneath  the  open  cuts.  This  incline,  which  is  no  longer  accessible, 
connected  with  the  Tuscarora  shaft  to  the  west  and  with  the 
Shesser  Bros,  and  McKay  shaft  to  the  east.  Old  maps  from  the 
files  of  W.  A.  Clark  show  several  stopes  just  north  of  the  Florida 
shaft.  This  shaft  was  80  feet  deep,  the  Shesser  Bros,  and  McKay 
shaft  130  feet,  and  the  Tuscarora  shaft  about  120  feet  deep.  All  of 
the  ore  from  the  Gov.  Tilden  claim  was  mined  by  underground 
methods.  About  300  feet  of  inclined  workings  were  opened  on  ore 
and,  in  addition,  about  600  feet  of  exploration  drifts  were  driven. 


78.  Personal  communication. 


MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


Bulletin  6,  Plate  XIV 


MAP  OF  THE  TUSCARORA  AND  GOV.  TILDEN  MINES 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA 


61 


The  ore  deposits  at  the  Tuscarora  and  Gov.  Tilden  mines  are 
in  the  gray  crystalline  Tilden  limestone  just  beneath  the  contact 
with  the  black  thin-bedded  Ermont  limestone.  The  limestone  beds 
strike,  in  general,  N.  20°  E.,  and  have  an  average  dip  of  about  25° 
SE.  The  principal  ore  shoots  were  pipe-like  in  cross  section  and 
followed  the  bedding  planes  of  the  limestone.  The  inclined  work- 
ing beneath  the  open  cuts  indicates  that  there  are  at  least  two 
productive  horizons.  The  shoots,  although  commonly  splitting 
around  blocks  of  limestone,  have  a definite  east-west  trend.  This 
trend  may  be  controlled  by  fissures,  but,  if  so,  they  are  not  clearly 
defined.  The  ore  is  displaced  by  a series  of  normal  faults,  striking 
north  and  northeast.  These  faults  have  steep  dips  which  vary  from 
70°  to  90°  and  are  characterized  by  well-defined  walls,  usually  sev- 
eral inches  of  gouge  and,  in  some  cases,  by  several  feet  of  breccia- 
tion.  The  Gov.  Tilden  ore  shoot  is  terminated  on  its  eastward  ex- 
tension by  one  of  these  faults  which  strikes  north  and  dips  about 
90°.  The  black  limestone  bed  with  the  twig-like  bodies  serves  as 
an  excellent  horizon  marker  for  structural  correlation. 

The  ore  was  almost  entirely  oxidized,  although  residual 
patches  of  galena  still  remain  along  the  walls  of  the  deposits.  A.  H. 
French79  describes  the  ore  from  the  Tuscarora  as  a “sand  carbonate” 
which  he  says  was  reported  to  assay  as  high  as  60  per  cent  lead 
and  60  ounces  silver.  The  average  metal  content  was  probably  con- 
siderably lower.  The  ore  was  shipped  directly  to  the  smelter  with- 
out concentration  and  with  very  little  sorting.  Ore  shipped  from 
the  Gov.  Tilden  in  1898-99  gave  gross  smelter  returns  of  $27.60 
per  ton.  The  average  quotations  for  lead  and  silver  for  those  years 
were  $4.12  and  59c,  respectively.  Assays  indicate  that  the  ore  car- 
ried $3  to  $5  per  ton  in  gold  and  that  the  ratio  of  silver  was  less 
than  one  ounce  to  the  unit  or  per  cent  of  lead.  On  the  basis  of  this 
ratio,  these  shipments  must  have  averaged  about  20%  lead.  This 
figure  is  in  accordance  with  the  metal  content  of  the  ore  shipped 
from  the  Gov.  Tilden  by  Messrs.  A.  H.  French  and  W.  G.  Graeter 
at  a later  date. 

Practically  no  commercial  ore  is  exposed  in  either  the  Tusca- 
rora or  Gov.  Tilden  at  the  present  time.  Some  low-grade  jasperoid 
wall-rock  remains  but  it  has  no  commercial  value  at  present.  A 
careful  study  of  the  normal  faulting  should  lead  to  the  discovery 
of  segments  of  the  faulted  ore  bodies.  Although  the  ore  shoots 
occasionally  split  around  limestone  blocks,  there  is  little  doubt  that 


79.  Personal  communication. 


62 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


they  were  continuous  on  the  dip  of  the  limestone  beds,  except  where 
displaced  by  faults. 

No  exact  measurements  were  secured  on  the  throw  of  the 
faults  so  that  the  position  of  the  ore  indicated  as  probable  in  the 
longitudinal  projection  through  the  Gov.  Tilden  ore  body  is  arbi- 
trarily placed  (PL  XIV).  Any  work  contemplated  in  these  proper- 
ties should  be  carefully  planned  and  all  available  sources  of  infor- 
mation should  be  consulted  in  order  to  determine  the  position  and 
extent  of  the  older  workings. 

The  Wooley  claim  overlaps  parts  of  the  Gov.  Tilden  and  Tusca- 
rora  claims.  Practically  all  of  the  work  on  the  Wooley  has  been 
confined  to  a 30-foot  inclined  shaft  and  an  open  cut  along  a fissure 
striking  N.  10°  W.,  and  dipping  about  90°.  Most  of  the  ore  occurred 
along  the  fissure  although  some  mineralization  is  evident  along  the 
bedding  planes.  The  production  from  the  Wooley  has  been  small. 

The  Florida  claim  is  situated  south  of  the  Gov.  Tilden  and  over- 
laps much  of  the  Tuscarora.  It  is  1,500  feet  long  by  550  feet  in 
width  and  was  located  with  the  long  direction  almost  at  right  angles 
with  the  Tuscarora.  Most  of  the  work  has  been  confined  to  the 
Shesser  Bros,  and  McKay  shaft,  the  Florida  shaft,  and  the  incline 
mentioned  above.  Some  pits,  a shallow  inclined  shaft  and  a short 
tunnel  have  been  opened  near  the  southern  boundary  of  the  claim. 
The  production,  which  could  not  have  been  large,  came  mostly  from 
the  incline  south  of  the  Tuscarora. 

The  Fraction  is  situated  south  of  the  Florida  and  Wooley  and 
overlaps  portions  of  each.  Practically  all  of  the  work  has  been  con- 
fined to  the  extreme  southwest  corner  of  the  claim  where  two 
shafts,  one  inclined,  and  several  cuts  have  been  opened.  Drifts  have 
been  run  from  the  bottom  of  the  shaft.  Small  stopes  indicate  that 
the  property  has  produced  some  ore.  The  ore  apparently  was  along 
bedding  planes  in  limestone  and  also  along  a well-defined  fissure 
cutting  across  the  limestone  beds.  The  ore  resembles  that  from 
the  Tilden  and  probably  had  about  the  same  metal  content. 

Little  or  no  work  has  been  done  on  the  Fraction  Placer,  Bur- 
leigh, Reform  or  Spring  claims.  The  buildings  are  located  on  the 
last-named  claim. 

TABULAR  ORE  SHOOTS  ALONG  BEDDING  PLANE  IN  LIMESTONE 

Only  one  important  property  in  the  Argenta  district,  the  Legal 
Tender,  has  produced  ore  solely  from  tabular  ore  shoots  along  bed- 
ding planes  in  limestone.  The  mineral-bearing  solution  may  have 
followed  fissures  in  its  course  upward,  but  development  work  has 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA  63 

thus  far  shown  the  ore  in  the  Legal  Tender  to  occur  only  along  the 
bedding  planes.  The  ore  follows  one  horizon  but  is  not  continuous 
along  it  for  it  pinches  out  laterally  and  is  displaced  by  faults.  In 
prospecting  ore  deposits  of  this  type,  unless  there  are  good  rea- 
sons to  suspect  that  other  bedding  planes  are  mineralized,  it  is  ad- 
visable to  follow  the  horizon  of  known  production. 

LEGAL  TENDER  MINE 

The  Legal  Tender  mine,  which  is  located  in  the  SE.14  of  sec.  24, 
was  discovered  in  1865  by  A.  M.  Esler  of  Bannack.  It  was  one  of 
the  first  silver-lead  mines  discovered  in  Montana  and  had  the  dis- 
tinction of  supplying  ore  for  the  first  smelter  built  in  the  state.80 
The  ore  was  at  first  shipped  to  Omaha  by  ox-teams,  from  there 
by  train  to  New  York  and  thence  across  the  Atlantic  to  Swansea, 
Wales.  George  M.  Brown  bought  the  property  from  Mr.  Esler  and 
leased  to  Cornelius  Bray,  who  mined  ore  worth  $10,000  from  a 
small  pocket.  Bray  also  shipped  some  ore  from  the  Colin  McDonald 
property,  just  south  of  the  Legal  Tender.  George  Dart  of  Dillon 
and  J.  A.  Brown  of  Melrose  later  acquired  an  interest  in  the  prop- 
erty. It  is  now  owned  by  James  Eddy,  a nephew  of  George  M. 
Brown,  and  the  J.  A.  Brown  estate.  The  production  of  the  Legal 
Tender  is  estimated  at  $150, 000.81 

The  ore  occurs  along  the  bedding  in  Tilden  limestone  not  far 
beneath  the  contact  with  the  Ermont  formation.  The  beds  in  the 
vicinity  of  the  mine  strike  N.  15°  E.,  and  dip  45°  S.  Most  of  the 
ore  was  mined  through  an  inclined  shaft  over  100  feet  in  depth 
which  is  now  only  partly  accessible.  The  stopes  average  about  four 
feet  in  width,  but  the  fresh  appearance  of  the  walls  suggests  that 
the  ore  body  may  have  been  narrower.  The  ore  was  a soft  “sand 
carbonate”  which  ran  about  300  ounces  in  silver  per  ton.  A few 
residual  patches  of  galena  remain  along  the  walls  near  the  termina- 
tion of  the  ore  shoots. 

SPANISH  MINE 

A small  ore  shoot  was  mined  on  the  Spanish  claim  about  500 
feet  north  of  the  Legal  Tender  ore  body.  The  workings  consist 
of  a shallow  shaft  and  some  small  stopes.  The  property  is  owned 
by  the  Anaconda  Copper  Mining  Company.  The  ore  occurs  along 
a bedding  plane  in  Tilden  limestone  which  here  strikes  N.  30°  E., 
and  dips  48°  S.  The  ore  appears  to  be  along  the  same  bed  as  the 
Legal  Tender  ore  shoot,  but  it  has  been  offset  50  feet  to  the  west 


80.  French,  George  W.  : Mining  Truth,  Spokane,  Wash.,  April  3,  1930,  p.  23. 

81.  French,  A.  H.,  personal  communication. 


64 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


by  steeply-dipping  faults  which  strike  N.  60°  W.  The  production 
of  the  Spanish  Lode  has  been  small. 

TABULAR  ORE  SHOOTS  ALONG  FISSURES  IN  LIMESTONE 

Tabular  ore  shoots  along  fissures  in  limestone  have  accounted 
for  a considerable  part  of  the  production  in  the  Argenta  region  and 
therefore  warrant  consideration.  The  ore  bodies  are  found  along 
steeply  dipping  fissures  and  are  usually  not  far  distant  from  igne- 
ous rocks.  The  fissures  are  well-defined  and  can  be  easily  traced. 
The  mineral-bearing  solution  of  course,  followed  the  fissures.  Cross 
fractures  are  common  but  most  of  them  appear  to  bear  no  relation 
to  the  ore  deposition.  The  junction  of  two  splits  in  the  Anaconda 
vein  tended  to  localize  the  ore  and  it  is  probable  that  pre-mineral 
cross-fractures  were  also  effective.  To  that  end,  no  important  cross- 
fractures were  noted  in  the  short  time  spent  in  the  examination  of 
these  mines  but  a more  thorough  examination  of  these  mines  would 
probably  reveal  them.  The  most  significant  structural  feature  noted, 
and  one  that  might  assist  in  the  search  for  ore,  is  the  “slickensided” 
fissures  and  slump  fractures  developed  in  the  vicinity  of  the  ore 
bodies.  It  seems  quite  clear  that  slumping  is  an  important  post- 
mineral process  which  should  be  a significant  aid  to  prospecting 
along  the  fissures. 

BROWNELL  MINE 

The  Brownell  claim  is  long  and  narrow  and  lies  partly  in  sec. 
19  and  partly  in  sec.  30.  It  was  located  in  1865  by  Harry  Griffiths, 
and  was  the  second  mine  discovered  in  the  Argenta  district.  Con- 
siderable ore  was  shipped  to  the  St.  Louis  & Montana  smelter  in 
the  late  ’sixties  and  early  ’seventies  by  E.  S.  Ball  and  others.  S.  H. 
Bohm  & Co.,  of  Helena  bought  the  Brownell  in  1871,  and  shipped 
ore  to  their  smelter.  A.  J.  Shoemacher  shipped  1,000  tons  of  ore 
to  the  St.  Louis  & Montana  smelter  during  the  years  1882-85.  The 
property  lay  idle  until  1890,  when  lessees  took  out  ore  worth  sev- 
eral thousand  dollars.  J.  E.  Oppenheimer  of  Butte,  Montana,  bought 
the  property  a short  time  later  and  it  is  still  owned  by  the  Oppen- 
heimer estate.  James  and  George  Knapp  shipped  20  cars  from  the 
west  vein  in  1922  and  George  D.  Spafford  has  since  shipped  eight 
cars  from  the  same  vein.  The  production  is  estimated  at  5,000  tons. 

The  Brownell  ore  bodies  were  worked  through  a shaft  which 
was  sunk  to  a depth  of  150  feet,  but  which  is  now  open  only  for 
110  feet.  Part  of  the  old  workings  are  no  longer  accessible.  The 
principal  working,  the  80-foot  level,  is  open  for  but  50  feet  south 
of  the  shaft.  The  ore  occurs  in  shoots  in  limestone  along  a well- 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA  65 

defined  fissure  which  strikes  north  and  dips  80°  W.  The  vein  splits 
on  its  downward  course  into  the  east  and  west  (“Knapp  stope”) 
veins.  A short  shoot  about  15  feet  wide  was  mined  at  the  junction 
of  the  splits  on  the  80-foot  level.  Stopes  with  an  average  width 
of  three  feet  and  a south  rake  extend  to  the  surface  on  the  north 
side  of  the  shaft.  The  “Knapp  stope”  pinched  and  swelled  but 
averaged  about  two  feet  in  width.  The  hanging  wall  is  slickensided 
and  highly  altered,  whereas  the  foot-wall  is  usually  a hard  crystal- 
line limestone  with  numerous  vugs.  The  “slickensided”  walls  have 
irregular  rolling  surfaces  and  in  places  show  copper  carbonate. 

The  ore  was  almost  entirely  oxidized  and  was  predominantly  a 
“sandy”  lead  carbonate.  Hard  jasperoid  ore  is  found  near  the  walls. 
The  ore  shipped  from  the  Knapp  stopes  averaged  28  per  cent  lead, 
and  shipments  by  Mr.  Spafford  averaged  31  per  cent  lead,  6 ounces 
per  ton  in  silver,  0.8  per  cent  copper  and  90  cents  per  ton  in  gold.81 
A small  car  of  ore  from  the  top  of  the  large  stope  on  the  80-foot 
level  contained  11  per  cent  copper. 

MAULDIN  MINE 

The  Mauldin  property  includes  two  claims,  the  Rittenhouse  and 
the  Louis  Philip,  which  are  located  in  the  NWT/2  sec.  29.  James 
Mauldin  located  the  property  and  did  considerable  prospecting.  He 
and  E.  S.  Ball  had  an  early-day  lawsuit  over  ownership  which  was 
decided  in  favor  of  Mauldin.  The  Mauldin  estate  has  recently  sold 
the  property  to  Frank  Wilson.  Four  shafts  and  a long  tunnel 
are  the  principal  openings,  but  only  part  of  them  are  now  accessible. 
The  deepest  shaft  was  sunk  in  limestone  to  intersect  the  quartz 
monzonite  contact,  but  was  abandoned  because  of  the  heavy  flow 
of  water.  No  ore  was  encountered.  Another  shaft  was  sunk  to  a 
depth  of  30  feet  on  a 50°  incline  and  then  20  feet  vertically.  Ore 
was  encountered  near  the  bottom  and  about  150  tons  were  mined. 
The  Eaton  shaft,  which  was  named  after  Professor  Eaton,  who  was 
probably  the  first  mining  geologist  in  the  district,  encountered  an 
ore  body  at  a depth  of  100  feet.  The  shaft  was  sunk  on  a fissure 
striking  N.  10°  W.,  which  dipped  80°  W.  The  wall  rock  next  to  the 
ore  body  is  strongly  “slickensided”  and  brecciated  material  resem- 
bling an  old  filling  occupies  fractures  near  the  top  of  the  stope. 
The  slickensides  and  brecciated  material  are  believed  to  have  formed 
from  slumping  due  to  the  shrinkage  which  resulted  from  the  re- 
moval of  material  during  oxidation  of  the  sulphide  ore.  Smith 
Ball  mined  the  ore  and  shipped  it  to  the  Stapleton  smelter.  No 


81.  Spafford,  George  D.,  personal  communication. 


66 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


figures  are  available  as  to  the  production  from  this  ore  body,  the 
old  stope  is  partly  filled  and  none  of  the  old  smelter  records  are 
available.  Soft  lead  carbonate  was  the  principal  ore  mineral.  The 
silver  content  was  about  3 ounces  per  ton  and  the  ore  carried 
about  $1.00  to  the  ton  in  gold.  The  ore  resembles  that  of  the 
Brownell  and  probably  had  a similar  metal  content,  although  the 
average  copper  content  is  said  to  have  been  higher. 

ANACONDA  MINE 

E.  S.  Ball  located  the  Anaconda  property  after  he  had  lost 
his  lawsuit  with  James  Mauldin.  He  sank  a 30-foot  shaft  and  en- 
countered an  ore  body,  and  later  he  sank  a working  shaft  60  feet 
deep.  The  ore  was  treated  at  the  St.  Louis  & Montana  smelter. 
Before  the  ore  body  was  worked  out  the  property  was  sold  to  the 
P.  J.  Kelly  Placer,  Quartz  & Reduction  & Smelting  Company,  who 
continued  to  ship  ore  to  the  smelter.  This  concern  finally  went  into 
receivership.  The  property  was  later  acquired  by  J.  E.  Oppenheimer 
of  Butte,  Montana. 

The  ore  occurred  as  an  irregular  tabular  body  along  the  Maul- 
din fissure,  a short  distance  north  of  the  Mauldin  incline.  The  ore 
was  largely  a soft  lead  carbonate  with  a low  silver  content.  The 
property  produced  about  500  tons  of  ore. 

COOLIDGE  MINE 

The  Coolidge  mine,  formerly  known  as  the  St.  Joseph,  was 
located  in  the  early  ’seventies  by  Thomas  E.  Tuttle,  and  is  situated 
in  the  SE.^i  of  sec.  18.  It  was  taken  over  by  E.  S.  Ball  who  shipped 
considerable  ore  to  the  St.  Louis  & Montana  smelter.  The  Golden 
Era  Company  then  sank  an  inclined  shaft  to  a depth  of  170  feet, 
but  made  no  shipments.  Alfred  Graeter  shipped  200  tons  of  ore 
from  the  dumps  in  1898.  The  property  was  later  located  by  Messrs. 
George  W.  and  A.  H.  French,  who  are  the  present  owners. 

The  ore  at  the  Coolidge  mine  is  enclosed  in  the  basal  beds  of 
the  Ermont  formation,  and  for  the  most  part  followed  along  a well- 
defined  fissure.  Near  the  surface  the  fissure  parallels  the  bedding 
but  steepens  and  leaves  the  bedding  at  a depth  of  40  feet.  A sill 
of  andesite  porphyry  forms  the  hanging-wall  of  the  ore  to  the  point 
where  the  vein  steepens.  The  ore  shoot  was  about  10  feet  high 
and  from  two  to  seven  feet  wide.  It  extended  for  about  100  feet 
beneath  the  surface  and  raked  to  the  south  at  an  angle  of  35°.  The 
stopes  indicate  a production  of  about  500  tons. 

The  ore  is  largely  oxidized  but  contains  residual  patches  of 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA 


67 


galena.  The  average  metal  content  is  about  10  per  cent  lead,  20 
ounces  in  silver,  and  $1.80  in  gold  per  ton. 

GOLDSMITH  MINE 

The  Goldsmith  mine  is  in  the  NE.%  of  sec.  30.  It  was  located 
in  the  late  ’eighties  by  Thomas  Judge  and  Thomas  Fox,  who  made 
no  shipments.  Mark  Bray  relocated  the  property  and  shipped  a 
little  ore,  but  soon  sold  a half  interest  to  a Mr.  Smeed.  Mr.  Bray’s 
half  interest  was  shortly  afterward  purchased  by  W.  A.  Clark,  who 
mined  most  of  the  ore  produced.  J.  E.  Oppenheimer  of  Butte,  Mon- 
tana, bought  the  Smeed  interest,  which  is  still  owned  by  the  Oppen- 
heimer estate.  In  the  transfer  of  1928,  the  Anaconda  Copper  Mining 
Company  acquired  the  Clark  interest.  A.  H.  French82  estimated  the 
production  of  the  Goldsmith  at  300  tons,  which  is  corroborated 
by  the  size  of  the  stopes. 

Access  to  the  property  is  gained  through  three  short  tunnels 
and  a shallow  incline.  One  tunnel  is  120  feet  long,  another  60  feet 
and  a third  25  feet  long.  The  second  and  third  and  the  incline  in- 
tersect the  ore  body,  but  the  first  has  encountered  only  brown- 
stained  marble.  The  ore  was  mined  in  underhand  stopes  which  are 
now,  for  the  most  part,  closed. 

The  ore,  found  along  a well-defined  fissure  in  a coarse-grained 
white  marble,  strikes  N.  80°  W.,  and  dips  70°  N.  The  ore  is  pre- 
dominantly hard  and  siliceous  and  is  irregular  in  width,  although 
it  is  never  wide.  The  principal  minerals  of  commercial  importance 
are  chrysocolla,  malachite,  tenorite,  cuprite,  copper  pitch,  native 
copper  and  gold.  Near  the  ore  bodies  the  marble  is  stained  a choco- 
late-brown color,  a fact  which  should  prove  a helpful  guide  in  pros- 
pecting for  further  ore,  particularly  as  the  outcrops  are  covered 
by  gravel.  According  to  Mr.  French,83  his  shipments  from  the  Gold- 
smith had  a gross  value  of  $75  per  ton. 

CONTACT  DEPOSITS  IN  LIMESTONE 

Two  types  of  contact  deposits  in  limestone  are  found  in  the 
Argenta  district.  Silver-lead  deposits  at  the  contact  between  quartz 
monzonite  and  Upper  Mississippian  limestones  are  represented  by 
the  Iron  Mountain  and  the  Argenta  Mining  Company’s  property, 
and  gold  deposits  at  the  contact  between  andesite  porphyry  and 
limestone  are  represented  by  the  Ermont  mine.  The  Iron  Mountain 
mine  which  belongs  to  the  first  group  has  been  one  of  the  important 
producers  in  the  district.  The  Argenta  Mining  Company’s  property 


82,  83.  French,  A.  H.  personal  communication. 


68 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


was  not  sufficiently  developed,  in  1929,  to  determine  its  worth.  The 
Ermont  mine  is  probably  the  newest  mine  in  the  Argenta  district, 
and  has  a tonnage  of  low-grade  gold  ore  partly  tested.  The  work 
on  the  property  is  being  directed  toward  proving  a low-grade  ore 
deposit  large  enough  to  justify  a mill. 

IRON  MOUNTAIN  MINE 

The  Iron  Mountain  mine  was  discovered  in  1869,  and  was 
worked  by  the  St.  Louis  & Montana  Mining  Co.,  and  later  by  E.  S. 
Ball,  who  purchased  both  the  mine  and  smelter  from  the  original 
company.  Mr.  Ball  sold  the  property  to  P.  J.  Kelly  Placer,  Quartz 
& Reduction  & Smelting  Company,  and  it  was  finally  acquired  by 
Oppenheimer  estate.  No  figures  are  available  as  to  the  production  of 
the  Iron  Mountain  mine,  but  the  size  of  the  stopes  indicates  that 
considerable  ore  was  produced.  Much  of  the  ore  was  shipped  to  the 
local  smelters  in  the  early  days.  The  mine  is  located  in  the  NE.ti 
of  sec.  30. 

Two  tunnels  and  two  inclined  shafts  are  the  principal  openings 
into  the  Iron  Mountain  mine.  The  longer  incline  started  in  quartz 
monzonite,  intersected  the  limestone  at  100  feet  and  continued 
down  the  contact  another  200  feet.  Near  the  bottom  the  shaft  be- 
comes very  flat.  The  upper  part  of  the  incline  is  no  longer  access- 
ible but  the  stopes  can  be  entered  through  the  lower  tunnel.  The 
lower  tunnel  starts  near  the  level  of  Rattlesnake  Creek  and  runs 
northward  about  700  feet  to  connect  with  the  longer  inclined  shaft. 
A considerable  head  of  water,  most  of  which  comes  from  near  the 
contact,  flows  from  this  tunnel.  Another  incline,  called  the  No.  1, 
is  caved  near  the  surface  but  access  can  be  gained  to  the  old  stopes 
through  the  Knapp  tunnel,  which  is  about  250  feet  long. 

The  ore  in  the  Iron  Mountain  mine  is  found  in  limestone  at  the 
contact  with  quartz  monzonite.  The  contact  is  usually  sharply 
marked  by  a band  of  white  altered  material  from  six  inches  to  a 
foot  wide.  The  ore  shoots,  where  observed,  were  more  or  less 
tabular  bodies  paralleling  the  contact  but  varying  considerably  in 
size  both  vertically  and  horizontally.  The  stopes  on  the  100-foot 
level  of  the  main  incline  have  a maximum  width  of  about  20  feet. 
These  stopes  are  said  to  have  reached  the  surface.  Steeply-dipping 
fractures  appear  to  have  localized  the  ore  in  the  vicinity  of  the 
Knapp  stope.  The  No.  1 incline  intersects  the  same  fissure  that  cuts 
the  most  productive  part  of  the  Knapp  ore  body.  The  enrichment 
along  the  north-south  fissures  may  not  have  been  primary. 

The  ore  is  almost  entirely  oxidized  although  residual  patches 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA  69 

of  galena  and  unaltered  pyrite  cubes  are  scattered  through  the  ore 
on  the  lower  levels.  The  richer  ore  is  massive  brown  cerussite  and 
limonite  with  patches  of  dark-gray  anglesite  and  irregular  green 
disseminations  of  malachite.  Malachite  stains  are  found  through- 
out the  ore  and  usually  a band  of  it  is  found  along  the  hanging  wall 
of  the  deposits.  Dark  gray  anglesite  of  a greasy  luster  is  the  pre- 
dominating ore  mineral  among  the  specimens  collected  from  the 
lower  level.  Native  copper  is  found  in  the  lower  stopes  and  was 
observed  in  lumps  as  large  as  6 inches  across.  It  is  mixed  with 
cuprite  and  malachite.  The  average  metal  content83  of  the  ore  ship- 
ped from  the  Knapp  stope  was  18  per  cent  lead,  12  oz.  silver,  and 
$3.00  in  gold  per  ton.  Three  cars  shipped  from  the  lower  workings 
had  a similar  metal  content. 

The  contact  in  the  vicinity  of  the  Iron  Mountain  mine  rarely 
carries  commercial  ore.  Nevertheless  the  contact  merits  careful 
prospecting.  The  heavy  flow  of  water  at  the  contact  should  be 
seriously  considered  before  attempting  work  below  the  level  of  the 
lower  tunnel. 

ERMONT  MINE 

The  Ermont  mine  property  includes  31  claims  which  lie,  for 
the  most  part,  in  sec.  30,  T.  6 S.,  R.  11  W.  The  claims  were  located 
in  1926  by  D.  V.  Erwin  and  W.  J.  Corbett,  who  prospected  the 
ground  until  1927,  when  the  property  was  bonded  to  the  Standard 
Silver  & Lead  Company  of  Spokane,  Washington.  This  company 
dug  several  trenches  and  sank  several  shallow  shafts  and  one  in- 
cline to  a depth  of  110  feet.  A drift  over  100  feet  long  was  run 
southward  from  the  bottom  of  this  shaft.  In  1929  the  property 
was  bonded  to  James  Kidwell  of  Portland,  Oregon,  who  was  oper- 
ating the  property  during  the  period  the  field  work  was  being 
done  for  this  report.  Some  ore  of  good  grade  has  been  shipped 
from  the  Yellow  Bird  claim  where  the  ore  occurs  along  a fissure  in 
limestone.  But  the  main  prospecting  at  the  Ermont  mine  has  been 
directed  toward  developing  a tonnage  of  low-grade  ore  sufficient 
to  justify  the  construction  of  a mill. 

Andesite  porphyry  has  been  intruded  into  the  Ermont  lime- 
stone in  the  vicinity  of  the  mine.  It  tends  to  follow  the  bedding 
planes  of  the  limestone,  but  in  some  places  clearly  cuts  across  the 
bedding.  Two  sill-like  bodies  of  andesite  porphyry  crop  out  east  of 
the  mine  but,  as  exposed  at  the  surface  and  in  the  prospect  holes, 
these  appear  to  join  and  form  a nearly  circular  southern  boundary. 


83.  Knapp,  George,  personal  communication. 


70 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


The  ore  is  found  in  limestone  at  the  contact  with  the  andesite 
porphyry,  which  is  usually  highly  altered  and  may  be  brown  or 
almost  white  in  color.  Next  to  the  ore  the  limestone  is  also  apt 
to  be  stained  a brown  color  and  to  have  a peculiar  mottled  appear- 
ance, which  has  caused  it  to  be  locally  termed  “zebra  limestone”. 
Fracture  zones  in  the  vicinity,  of  the  mine  strike  north  of  east. 
The  limestone  in  the  vicinity  of  these  fractures  has  been  highly 
silicified  and  in  places  carries  gold  and  silver.  The  ore  in  the 
vicinity  of  the  main  shaft  also  is  frequently  siliceous,  though  it  is 
more  often  a soft  porous  non-siliceous  material.  Large  irregular 
bodies  of  a low-grade  ore  have  been  prospected  near  the  surface. 
A sample  of  the  oxidized  ore  from  the  lower  tunnel  assayed  25  oz. 
in  silver  and  $2.00  in  gold  per  ton.  This  sample,  which  was  taken 
by  the  writer,  was  higher  in  silver  and  lower  in  gold  than  the 
average. 

ARGENTA  MINING  CO.  PROPERTY 

The  Argenta  Mining  Co.  property  consists  of  five  patented 
claims  and  six  unpatented  claims.  The  company  was  organized  in 
1928  by  Judah  Judah  of  Argenta,  G.  V.  Elder  and  Ralph  Rowlands 
of  Dillon,  Montana.  The  upper  tunnel,  which  intersects  an  oxidized 
ore  body,  is  60  feet  long  and  a winze  55  feet  deep  has  been  sunk  at 
the  end  of  this  tunnel.  A lower  level,  100  feet  below  the  upper 
level,  has  been  driven  180  feet  toward  the  ore  body  exposed  in  the 
upper  tunnel  but  had  not  reached  it  in  1930.  All  of  this  work  has 
been  done  on  the  Sir  Walter  Scott  claim. 

The  ore  occurs  at  the  contact  between  quartz  monzonite  and 
limestone.  All  the  limestone  except  a small  outcrop  is  covered  with 
the  “upper  bench  gravels”  on  the  surface.  The  ore  is  entirely  oxi- 
dized and  consists  largely  of  a soft  porous  limonite  said  to  carry 
considerable  gold.  Bismutite  (hydrous  basic  bismuth  carbonate)  is 
found  with  the  oxidized  material.  Some  ore  has  been  shipped. 

DEPOSITS  ALONG  FISSURES  AND  SHEAR  ZONES  IN  QUARTZITE 

The  deposits  along  fissures  and  sheer  zones  in  quartzite  have 
not  accounted  for  much  of  the  production  in  the  Argenta  district. 
The  Carbonate  has  been  the  most  important  mine  of  this  group, 
but  thus  far  the  ore  has  not  been  continuous.  Deposits  of  the 
Groundhog  type  where  quartz  and  gold  have  been  introduced  into 
brecciated  quartzite  along  a well-defined  fault  fissure  warrant  more 
attention,  provided  the  sampling  proves  the  ore  to  be  of  commercial 
grade. 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA 


71 


CARBONATE  MINE 

The  Carbonate  mine  is  in  the  NW.14  of  sec.  18,  and  was  located 
by  Phil  M.  Brown  in  1890.  He  shipped  about  10  cars  to  the  local 
smelters  and  then  sold  the  property  to  the  St.  Louis  & Montana  Co., 
who  sank  a shaft  to  a depth  of  75  feet  near  the  south  end-line  of 
the  Rena  claim.  The  property  was  relocated  by  W.  M.  McMannis 
and  Alfred  Graeter,  and  was  finally  acquired  by  A.  H.  French  and 
George  W.  French  of  Argenta,  who  are  the  present  owners.  Mc- 
Mannis and  Graeter  mined  some  ore  but  practically  all  of  the  pro- 
duction is  credited  to  Mr.  Brown.  The  main  shaft  is  90  feet  deep 
and  several  shallower  shafts  have  been  sunk  besides  the  75-foot 
shaft  sunk  by  the  St.  Louis  & Montana  Co. 

The  ore  is  found  in  a well-defined  vein  in  Flathead  quartzite. 
The  vein  strikes  N.  70°  W.,  and  dips  70°  S.,  at  the  surface  but  re- 
verses to  a northerly  dip  at  40  feet  depth.  A grayish-green  ande- 
site porphyry  dike  follows  along  the  hanging-wall  of  the  ore  and  in 
one  place  a segment  of  the  vein  is  offset  50  feet  to  the  west.  The 
ore  occurs  in  lenses  and  is  broken  and  associated  with  gouge.  Most 
of  the  ore  shipped  was  a dark-gray  lead  carbonate. 

GROUNDHOG  MINE 

The  Groundhog  mine  is  southeast  of  the  Carbonate,  in  sec.  18. 
A.  H.  French  and  George  W.  French  located  the  property  in  1895, 
and  have  shipped  one  car  of  ore  which  assayed  $20  per  ton  in  gold. 
Shallow  shafts  have  been  dug  along  the  vein  at  intervals  for  over 
1,100  feet,  and  a shaft  100  feet  deep  has  been  sunk  near  the  portal 
of  the  principal  tunnel  which  is  75  feet  long. 

The  ore  occurs  in  Flathead  quartzite  along  a fault  fissure  which 
strikes  N.  30°  W.,  and  dips  80°  N.  The  quartzite  has  been  brecciated 
for  a width  of  three  feet  along  the  fault,  and  this  brecciated  ma- 
terial has  been  re-cemented  with  quartz  carrying  gold  and  pyrite. 
The  vein  is  strongly  marked  by  slickensides,  and  horizontal  stria- 
tions  are  very  well  defined. 

DEPOSITS  ALONG  FISSURES  IN  SHALE 

Deposits  along  fissures  in  shale  have  probably  produced  ore 
valued  at  $200,000.  They  have  been  the  source  of  a considerable 
part  of  the  gold  production  of  the  district  as  well  as  much  of  the 
lead  and  silver.  Because  of  the  nature  of  the  wall-rock,  most  of 
the  underground  openings  are  now  caved,  and  little  information  can 
be  gained  regarding  the  underground  geological  conditions.  A con- 
siderable expenditure  would,  in  most  cases,  be  necessary  to  recon- 
dition the  old  workings  for  a development  program. 


72 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


GOLDEN  ERA  MINE 

The  Golden  Era  mine,  which  is  in  the  NE.^4  of  sec.  13,  was 
discovered  in  1880,  by  W.  D.  Booth.  It  was  afterward  re-located 
by  A.  I.  Watts,  but  neither  locator  shipped  ore.  George  W.  French 
and  Henry  Laughlin  bought  the  property  in  1884  and  shipped  a 
small  tonnage  to  local  smelters.  The  St.  Louis  & Montana  Mining 
Co.  purchased  the  mine  and  shipped  considerable  ore  besides  taking 
out  about  1,000  tons  of  second-class  material  which  was  later  milled 
by  a Mr.  Taylor.  The  prospect  is  now  owned  by  the  J.  F.  Imbs 
estate. 

An  inclined  shaft  300  feet  deep  is  the  principal  entry  into 
the  mine.  The  shaft  starts  in  thin-bedded  quartzite  but  enters 
green  and  red  shales  at  a depth  of  10  feet.  The  shaft  is  now  closed 
20  feet  below  the  collar.  The  ore  occurs  in  a well-defined  vein, 
striking  about  N.  5°  E.,  and  dipping  60°  S.,  at  the  surface.  The 
shale  beds  dip  at  flat  angles  to  the  south  in  the  vicinity  of  the 
mine.  The  vein  has  been  stoped  to  the  surface  near  the  shaft  and 
was  from  one  to  four  feet  wide.  The  best  ore  consisted  principally 
of  galena  and  pyrite  in  a quartz  gangue  and,  although  water  was 
encountered  at  a depth  of  60  feet,  the  ore  was  partly  oxidized  on 
the  bottom  level.  Five  carloads  of  the  ore  had  an  average  metal84 
content  of  25  per  cent  lead,  21.54  oz.  silver,  and  4.35  oz.  gold  per  ton. 

RENA  MINE 

The  Rena  mine  is  in  the  NW.Vi  of  sec.  18,  and  was  located  by 
Homer  Lawrence  and  John  Miles  in  1884.  They  sank  a shaft  to  a 
depth  of  70  feet  and  shipped  considerable  ore  to  smelters  in  Omaha, 
Nebraska.  They  sold  the  property  to  the  St.  Louis  & Montana 
Mining  Co.,  who  sank  a shaft  to  a depth  of  300  feet  and  made  a 
crosscut  to  the  vein.  The  St.  Louis  & Montana  Co.  shipped  only  a 
small  amount  of  ore,  but  lessees  later  made  some  shipments.  A.  H. 
French  acquired  the  property  in  1922.  He  estimates  a production 
of  250  to  300  tons. 

The  ore  occurred  as  a shoot  60  feet  long  in  a well-defined  vein 
which  is  in  flat-dipping  Spokane  beds.  Caved  stopes  indicate  that 
ihe  vein  had  a strike  of  about  N.  40°  W.,  and  a dip  of  about  60°  S., 
but  according  to  Mr.  French85  the  vein  turned  and  dipped  to  the 
north  near  the  bottom  of  the  deeper  shaft.  A fault  is  said  to  have 
terminated  the  ore  shoot  on  the  south.  The  primary  ore  minerals 
include  principally  pyrite  and  galena  with  gold  and  silver  in  a 


84.  From  smelter  returns  given  to  A.  H.  French  by  J.  F.  Imbs. 

85.  French,  A.  H.,  personal  communication. 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA  73 

quartz  gangue.  Much  of  the  sulphide  ore  on  the  dump  is  in  brecci- 
ated  quartzite,  which  has  been  recemented  with  quartz  and  sulphide 
minerals.  Very  little  oxidation  was  found  below  water  level  at  40 
feet.  Shipments  by  Mr.  French86  assayed  20  per  cent  lead  and  2.0  oz. 
in  gold  per  ton,  but  the  oxidized  ore  shipped  by  Lawrence  and  Miles 
is  said  to  have  had  an  average  gold  content  of  about  5 oz.  per  ton. 

MIDNIGHT  MINE 

The  Midnight  mine  is  in  the  SE.14  of  sec.  13.  The  mine  was 
located  by  Robert  Wing  in  the  early  ’seventies.  He  sank  a shaft 
to  a depth  of  60  feet,  but  made  no  shipments.  H.  R.  Paddock  and 
Fred  Randolph  later  relocated  the  property  and  shipped  some  ore. 
A.  V.  Clark  bought  the  mine  and  worked  it  for  several  years.  He 
shipped  considerable  ore  and  then  sold  to  the  Monida  Trust  Co., 
which  still  retains  the  ownership.  The  property  has  probably  pro- 
duced87 50  cars  of  ore  with  a gold,  silver  and  lead  value  of  about 
$40  per  ton. 

The  principal  openings  at  the  Midnight  mine  consist  of  five 
shafts,  one  265  feet  deep,  another  180  feet,  one  150  feet,  one  80 
teet,  and  a fifth  60  feet  deep.  The  ore  in  places  has  been  stoped 
to  the  surface.  Most  of  the  workings  are  now  inaccessible.  The 
vein  is  in  flat-lying  Spokane  shales  and  quartzites  and  strikes  N 
40°  W.,  and  dips  70°  N.,  at  the  surface.  It  varies  considerably  in 
width  and  in  some  places  splits  around  “horses”  of  shale.  The  prin- 
cipal primary  ore  minerals  are  galena  and  pyrite  in  a quartz  gangue. 
Oxidation  has  extended  downward  for  a distance  of  about  200  feet. 

GOLDFINCH  MINE 

The  Goldfinch  property,  which  includes  five  claims,  is  in  the 
NW.14  of  sec.  24.  The  original  location  was  made  in  the  late  ’eigh- 
ties by  A.  V.  Clark.  He  dug  a number  of  surface  pits,  sank  one 
shaft  to  a depth  of  60  feet  and  shipped  several  cars  of  ore.  The 
property  was  purchased  in  1890  by  George  W.  French  and  A.  H. 
French,  who  are  the  present  owners.  Since  1890  owners  and  lessees 
have  worked  the  mine  intermittently.  The  total  production  is  about 
250  tons. 

An  inclined  shaft  at  the  north  end  of  the  Dolphin  claim  is  th<; 
principal  entry  into  the  mine.  Stopes  have  been  opened  on  the 
north  and  south  sides  of  the  shaft  for  a distance  of  120  feet.  The 
ore  is  in  shoots  along  a well-defined  vein  in  Spokane  shale.  A highly 
altered  porphyrytic  dike  follows  along  the  vein.  The  dike  is  irregu- 


86,  87.  French.  A.  H. , personal  communication. 


74 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


Jar  in  width  and  the  walls  are  considerably  “slickensided”.  The  vein 
varies  from  about  one  to  seven  feet  in  width.  The  ore  is  in  shoota 
in  the  vein  and  is  partly  oxidized  even  on  the  lower  level.  The  pri- 
mary minerals  are  principally  pyrite  and  galena  in  a quartz  gangue. 
Shipments  of  the  ore  ran  from  0.8  to  1.20  oz.  in  gold,  from  7 to  15 
oz.  in  silver  per  ton,  and  about  7 per  cent  lead. 

A tunnel  has  been  run  for  200  feet  along  a shear-zone  in  Flat- 
bead  quartzite  on  the  south  end  of  the  Dolphin  claim.  The  quartzite 
is  sheared  and  brecciated  for  a width  of  12  feet.  No  shipping  ore 
has  been  encountered  in  the  quartzite. 

DEXTER  MINE 

The  Dexter  mine  is  in  the  NW.14  of  sec.  17.  The  nearest  ship- 
ping point,  Bond,  is  on  the  Oregon  Short  Line  railroad,  seven  miles 
to  the  west.  The  property  consists  of  six  claims  and  was  being 
operated  in  1929  by  the  Continental  Divide  Mines  Company,  under 
the  direction  of  W.  J.  Cushing.  The  old  workings  are  no  longer 
accessible  but  according  to  Mr.  Cushing88  the  ore  was  exceptionally 
high-grade  in  silver.  William  Dudley  shipped  most  of  the  ore  in 
the  early  ’eighties  but  considerable  work  was  later  done  by  the  St. 
Louis  & Montana  Co.  Following  this  very  little  work  was  under- 
taken until  1929,  when  the  Continental  Divide  Mines  Co.  started  an 
exploration  program. 

Several  shafts  were  sunk,  one  by  the  St.  Louis  & Montana  Co., 
to  a depth  of  317  feet.  It  is  connected  with  the  surface  by  a tunnel 
260  feet  long.  A crosscut  from  this  tunnel  enters  the  old  stopes, 
now  inaccessible.  The  principal  ore  deposits  were  found  in  veins 
in  shale  not  far  from  the  contact  with  granodiorite.  Almost  the 
entire  length  of  the  tunnel  passes  through  brecciated  rocks  cut  by 
a number  of  well-defined  fault  surfaces.  The  old  stopes  are  situated 
to  the  southwest  of  the  tunnel.  Fragments  of  the  ore  on  the  dump 
are  composed  mainly  of  partly  oxidized  galena,  pyrite  and  tetrahe- 
drite. 

Some  contact  metamorphic  deposits  in  limestone  have  been  ex- 
plored in  the  flat  northeast  of  the  St.  Louis  & Montana  Co.  shaft. 
The  limestone  is  garnetized  and  contains  much  recrystallized  cal- 
cite.  In  1929  the  principal  operations  consisted  in  sinking  the  Galena 
shaft,  which  is  about  2,000  feet  southeast  of  the  old  mine.  The  shaft 
had  been  sunk  to  a depth  of  60  feet  on  a vein  striking  S.  20°  E.,  with 
a dip  of  70°  S.  The  enclosing  rock  is  largely  garnetized  limestone 
with  granodiorite  along  the  hanging-wall  at  a depth  of  20  feet. 


88.  Cushing,  W.  J.,  personal  communication. 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA 


75 


The  vein  had  widened  from  a few  inches  near  the  surface  to  about 
two  feet  near  the  bottom  of  the  shaft.  The  ore  consists  mostly  of 
galena,  pyrite  and  some  tetrahedrite.  It  is  partly  oxidized  on  the 
bottom  level. 

GLADSTONE  MINE 

The  Gladstone  and  Argenta  claims  comprise  the  Gladstone 
group.  They  are  in  the  SE.}4  of  sec.  13,  T.  6 S.,  R.  11  W.,  and  were 
located  in  the  late  ’eighties,  the  Gladstone  by  Mark  Bray  and  the 
Argenta  by  James  McKay.  The  Argenta  produced  150  tons  but  the 
Gladstone  has  had  little  or  no  production.  The  J.  E.  Morse  estate 
of  Dillon,  George  W.  French  of  Argenta,  and  the  Amede  Bessette 
estate  of  Bannack,  Montana,  own  the  property. 

A shaft  200  feet  deep  has  been  sunk  on  the  Argenta  and  a few 
drifts  were  run  from  it.  The  principal  working  on  the  Gladstone 
claim  is  a 50-foot  shaft.  Neither  shaft  is  now  accessible.  The  vein, 
which  strikes  N.  45°  W.,  and  dips  80°  N.,  is  in  the  shale  and  thin- 
bedded  quartzite  of  the  Spokane  formation.  Much  brecciated  ma- 
terial cemented  with  calcite  is  found  on  the  dumps  of  the  Argenta 
claim;  the  vein  is  said  to  have  entered  “clay”  near  the  bottom. 
The  principal  value  of  the  ore  was  in  gold,  although  it  carried  con- 
siderable lead.  The  ore  from  the  Argenta  claim  carried  $50  per  ton 
in  gold,  but  that  in  the  Gladstone  shaft  was  of  much  lower  grade. 
A vein  five  to  six  feet  wide  and  carrying  $12  per  ton  in  gold  is  said 
to  exist  at  the  bottom  of  the  Gladstone  shaft. 

ORE  SHOOTS  ALONG  VEINS  AND  SHEAR  ZONES 
IN  QUARTZ  MONZONITE 

The  most  recent  notable  production  in  the  Argenta  region  has 
come  from  the  Ferdinand  mine,  a deposit  in  quartz  monzonite.  The 
ore  was  of  shipping  quality  and  occurred  in  a good-sized  deposit. 
Prospecting  is  made  difficult  at  present  by  the  condition  of  the 
shaft.  Little  water  was  found  in  the  Ferdinand,  but  water  became 
a serious  problem  in  the  lower  level  of  the  Jack  Rabbit  mine. 

FERDINAND  MINE 

The  Ferdinand  group  is  in  the  SE.i/4  of  sec.  29,  and  consists 
of  11  small  claims  100  by  200  feet  in  size.  The  mine  was  discovered 
in  1868  by  Thomas  Harrison,  who  shipped  some  ore  to  Swansea, 
Wales;  later  the  Ferdinand  ores  were  treated  at  local  smelters. 
Mining  ceased  when  the  sulphide  ores  were  reached  and  the  prop- 
erty lay  idle  for  20  years,  until  the  St.  Louis  & Montana  Mining 
Co.  were  able  to  treat  the  sulphide  ore  by  giving  it  a preliminary 


76 


BULLETIN  6,  MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


roast.  The  mine  supplied  ore  to  the  Argenta  smelters  for  two  years 
at  this  period.  LaFayette  Scott  acquired  the  property  from  the  St. 
Louis  Co.,  and  it  was  owned  by  his  estate  until  1909,  when  his  ad- 
ministrator sold  it  to  the  Argenta-Dillon  Mining  Company.  This 
company  opened  up  the  shaft  and  shipped  some  ore.  In  1925  G.  A. 
Decker  and  Roy  B.  Herndon  of  Dillon  secured  a lease  and  stoped 
ore  from  the  80-foot  level.  In  1927-28  Mr.  Decker  and  Harry  Renz 
of  Argenta  shipped  17  cars  from  the  same  ore  body.  Theodore 
Nelson,  William  D.  Ross  and  Martin  Sorensen  of  Dillon  now  own 
the  Ferdinand. 

A shaft  115  feet  deep  is  the  principal  entry  into  the  mine. 
One  level  was  opened  northwest  of  the  shaft  at  a depth  of  80  feet, 
and  another  near  the  bottom  of  the  shaft.  The  ore  occurs  near 
the  contact  of  quartz  monzonite  with  Mississippian  limestone  along 
a shear  zone  which  strikes  N.  30°  W.,  and  dips  90°.  The  stopes 
are  now  caved  in  but  during  the  writer’s  visit  to  the  property  in 
1927,  about  12  feet  of  ore  was  exposed  in  the  face  of  the  drift.  It 
was  not  solid  ore  but  sulphide  material  alternating  with  bands  of 
soft,  highly  altered  and  partly  mineralized  quartz  monzonite.  Part 
of  the  material  was  shipped  as  it  was  mined  and  part  of  the  material 
was  sorted.  A carload  of  the  better  grade  material  contained  22.1 
per  cent  lead,  15.5  per  cent  zinc,  1.18  per  cent  copper,  6.1  per  cent 
iron,  8.5  oz.  silver,  and  0.01  oz.  gold  per  ton.  A carload  of  unsorted 
ore  contained  10.4  per  cent  lead,  12.5  per  cent  zinc,  0.54  per  cent 
copper,  6.0  per  cent  iron,  4.1  oz.  silver,  and  0.01  oz.  gold.  The  prin- 
cipal minerals  in  the  sulphide  ore  are  galena,  sphalerite,  chalcopy- 
rite  and  pyrite.  Polished  sections  show  the  presence  of  pyrargyrite 
in  small  amounts.  Chalcopyrite  is  disseminated  through  the  sphal- 
erite as  oriented  grains,  some  less  than  1/400  of  a millimeter  across 
but  with  an  average  diameter  of  about  1/200  of  a millimeter.  The 
ore  is  only  slightly  oxidized  at  a depth  of  80  feet.  Because  of  the 
clay-like  nature  of  the  wall-rock  next  to  the  ore,  considerable  diffi- 
culty was  experienced  in  preventing  caves. 

JACK  RABBIT  MINE 

The  Jack  Rabbit  mine,  which  has  the  distinction  of  being  the 
deepest  mine  in  the  Argenta  district,  is  in  the  NW.^4  of  sec.  29, 
about  one-half  mile  northeast  of  Argenta.  It  was  discovered  by 
J.  P.  Fletcher  in  the  ’seventies,  on  a small  outcrop  of  the  ore.  An 
inclined  shaft  was  sunk  to  the  140-foot  level.  The  Conda  Mining 
Company  operated  the  property  from  1915  to  1919,  and  sank  a 
shaft  to  a depth  of  300  feet,  besides  running  200  feet  of  crosscuts 


GEOLOGY  AND  ORE  DEPOSITS  OF  BANNACK  AND  ARGENTA  77 

on  the  200  and  300  levels  to  the  Jack  Rabbit  and  Copper  Bell  veins. 
Water  was  encountered  at  90  feet,  and  at  a depth  of  300  feet  two 
pumps  were  used  to  handle  the  flow.  The  shaft  is  now  closed. 
The  Conda  Mining  Company  shipped  about  15  cars  of  ore.89 

The  ore  is  in  quartz  monzonite  not  far  from  the  contact  with 
limestone.  The  ore  from  the  lower  levels  consists  principally  of 
chalcocite  and  pyrite  in  a quartz  gangue.  The  ore  shipped  by  George 
D.  Spafford  assayed  16  per  cent  copper  and  32  oz.  silver  per  ton.90 

COPPER  BELL  MINE 

The  Copper  Bell  claim  is  half  a mile  north  of  Argenta,  and 
west  of  the  Jack  Rabbit.  It  was  located  in  the  late  ’seventies  by 
J.  P.  Fletcher,  and  later  relocated  by  A.  J.  Shoemacher,  who  did 
most  of  the  work  on  the  property.  Mr.  Shoemacher  let  the  prop- 
erty go  by  default  and  it  was  relocated  by  Alexander  Pilon,  who 
sold  it  to  J.  E.  Oppenheimer  estate  and  William  B.  Orem  of  Butte. 
The  production  has  been  small,  probably  not  over  one  car. 

The  Copper  Bell  vein  is  opened  by  a shaft  112  feet  deep  and 
has  been  prospected  for  a short  distance  along  the  strike  on  three 
levels,  the  45,  the  60  and  the  112-foot  levels.  The  shaft  is  now 
filled  to  the  60-foot  level.  The  ore  occurs  along  a vein  in  quartz 
monzonite  near  the  limestone  contact.  The  vein,  which  has  “slick- 
ensided”  walls,  strikes  N.  5°  E.,  and  dips  about  80°  SE.  The  ore  is 
entirely  oxidized  on  the  60-foot  level  but  is  said  to  be  largely  sul- 
phides on  the  lower  level.  The  oxidized  ore  minerals  include  cuprite, 
chrysocolla,  malachite,  copper  pitch,  and  limonite.  One  car  of  ore 
shipped  by  Mr.  Shoemacher  ran  10  per  cent  copper  and  carried  some 
silver  and  gold.  Oxidized  ore  at  the  surface  assays  $20  in  gold 
per  ton. 

BELLA  MINE 

The  Bella  mine  is  on  the  outskirts  of  Argenta  on  the  south  side 
of  Rattlesnake  Creek.  It  was  located  by  A.  H.  French  in  1906,  and 
was  called  the  Whopper.  In  1907,  the  Argenta  Mining  Co.,  of  Dillon, 
sank  a shaft  to  a depth  of  200  feet  and  made  a crosscut  20  feet  to 
a vein  striking  north.  The  vein  was  solid  sulphide  material  con- 
sisting of  pyrite  and  a little  galena  and  sooty  chalcocite.  The  vein 
starts  in  quartz  monzonite,  but  encounters  limestone  at  50  feet.91 
The  outcrop  contains  cuprite,  malachite,  tenorite,  and  limonite.  The 
vein  is  about  three  feet  wide  at  the  surface,  but  mineralization  ex- 
tends for  several  feet  on  either  side  of  the  vein. 


89,  90.  Spafford,  George  D.,  personal  communication. 
91.  French,  A.  H.,  personal  communication. 


INDEX 


Page 

Acknowledgments  8 

Age  of  volcanic  rocks 25 

Algonkian  system  at  Argenta 45 

Anaconda  mine  66 

Andesite  in  Bannack  area........ 23 

Andesite  porphyry  52 

Argenta  area  45 

Algonkian  system  in 45 

Cambrian  system  in 46 

Carboniferous  system  in 48 

Deformation  in  56 

Devonian  system  in 47 

extrusive  igneous  rocks  in 55 

faulting  in  56 

folding  in  56 

geology  of  % 45 

history  of  67 

intrusive  igneous  rocks  in 50 

ore  deposits  in 57 

ore  deposits,  classification  of 58 

Quaternary  deposits  in 50 

Spokane  formation  in 45 

Argenta  Mining  Co 70 

Atwood,  W.  W.,  reference  to 11-17 

Bannack  and  Argenta, 

geography  of 10 

topography  of  10 

Bannack  area,  the 14 

andesite  in  23 

basalt  in  25 

carboniferous  system  in 14 

contact  effects  in 21 

dacite  in  24 

dikes  in  22 

extrusive  rocks  in 22 

faulting  in  25 

folding  in  25 

gangue  minerals  of  31 

general  geology  14 

granodiorite  in  18 

history  of  26 

Madison  formation  in  14 

Mesozoic  system  in 16 

mineralogy  of  ores 28 

ore  deposits  of  26 

ore  minerals  of  29 

placer  deposits  at  43 

placers,  production  of  44 

production  of 28 

Quadrant  formation  in  15 

red  beds  in  16 

rhyolite  in  24 

rocks  of  14 

Tertiary  gravels  in  17 


Page 

Bannack  Gold  Mining  & Smelting 


Company  40 

Bannack  Mining  District  39 

Basalt  in  Bannack  area 25 

Bella  mine  77 

Bibliography  13 

Billingsley,  P.,  reference  to  . ..17-18-57 

Blue  Grass  mine  42 

Blue  Wing  Mining  District 32 

Browne,  J.  R.  reference  to  57 

Brownell  mine  64 

Butler,  B.  S.,  reference  to  39 

Calkins,  F.  C., 


Calvert,  W.  R.,  reference  to  22 

Cambrian  system  at  Argenta  46 

Carbonate  mine  71 

Carboniferous  system  at  Argenta  ..  48 

Charter  Oak  mine  38 

Classification  of  Argenta 

ore  deposits  58 

Climate  12 

Condit,  D.  D.,  reference  to  16-17 

Contact  effects  in  Bannack  area  ....  21 

Coolidge  mine  66 

Copper  Bell  mine  77 

Coppin,  J.,  reference  to  36 

Cushing,  W.  J.,  reference  to 74 

Dacite  in  Bannack  area  24 

Dacite  porphyry  53 

Darton,  N.  H.,  reference  to  17 

Deformation  in  Argenta  area  56 

Del  Monte  mine  34 

Devonian  system  at  Argenta  47 

Dexter  mine  74 

Dikes  in  Bannack  area  22 

Douglas,  E.,  reference  to  22 

Dunn,  William,  reference  to  40-44 

Emmons,  W.  H.,  reference  to,  16-22-39 

46-47-56 

Ermont  formation  47 

Ermont  mine  69 

Excelsior  mine  40 

Extrusive  igneous  rocks  at 

Argenta  55 

in  Bannack  area  22 

Faulting  at  Argenta  56 

in  Bannack  area  25 

Ferdinand  mine  75 

Flathead  formation  46 

Florida  mine  59 

Folding  at  Argenta  56 

in  Bannack  area  25 


INDEX 


Page 

French,  A.  H.,  reference  to.. ..60-63-67 

72-73-77 

French,  G.  W.,  reference  to  57-63 

Gangue  minerals  of  Bannack  area..  31 

Geography  of  Bannack  and 

Argenta  10 

Glacial  moraine  50 

Gladstone  mine  75 

Gold  Bug  mine  42 

Golden  Era  mine 72 

Goldfinch  mine  73 

Golden  Leaf  group  41 

Goldsmith  mine 67 

Governor  Tilden  mine  59 

Granodiorite  at  Argenta  51 

in  Bannack  area  18 

Gravels,  auriferous  in  Bannack 

area  17 

Tertiary  at  Argenta  49 

Tertiary  in  Bannack  area  17 

Groundhog  mine  71 

Hand,  Carl,  reference  to  ........40-41-42 

Hendricks  mine  43 

History  of  Argenta  57 

of  Bannack  area  26 

Huron  mine  37 

Imbs,  J.  F.,  reference  to  72 

Ingersoll  mine  38 

Intrusive  igneous  rocks  at  Argenta  50 

Iron  Mask  mine  38 

Iron  Mountain  mine 68 

Jack  Rabbit  mine  76 

Kemp,  J.  F.,  reference  to  17 

Kent  mine  32 

Knapp,  G.,  reference  to 69 

Knopf,  A.,  reference  to  22-25 

Legal  Tender  mine  63 

Lindgren,  W.,  reference  to  32-39 

Mansfield,  G.  R.,  reference  to  56 

Mathew,  W.  D.,  reference  to  22 

Mauldin  mine  65 

Mesozoic  system  in  Bannack  area..  16 

Midnight  mine  73 

Mineralogy  of  Bannack  ores  28 

Mississippian  series  48 


Page 

New  Departure  mine  36 

O’Leary,  J.  F.,  reference  to  32 

Ore  deposits  at  Argenta  57 

Ore  deposits  of  Bannack  area  26 

Ore  minerals  of  Bannack  area 29 

Pardee,  J.  T.,  reference  to  45-49-56 

Peale,  A.  C.,  reference  to 14-46-47 

Pennsylvanian  series  49 

Placer  deposits  at  Bannack  43 

Pomeroy  mine  37 

Prescott,  B.,  reference  to  59 

Production  of  Bannack  area  28 

of  Bannack  placers 44 

Quartz  monzonite  51 

Quaternary  deposits  at  Argenta  ....  50 

Randall  mine  37 

Raymond,  R.  W.,  reference  to  37 

Red  beds  in  Bannack  area  16 

Rena  mine  72 

Rhyolite  in  Bannack  area 24 

Rhyolite  porphyry 54-55 

Richards,  R.  W.,  reference  to,  45-49-56 

Shenon,  P.  J.,  reference  to 42 

Silver  Star  mine  38 

Sinott,  F.  F.,  reference  to  37-39 

Spafford,  G.  D.,  reference  to  65-77 

Spanish  mine  63 

Spokane  formation  at  Argenta 45 

Stallings,  C.  W.,  reference  to  43 

Stone,  R.  W.,  reference  to  22 

Tertiary  gravels  at  Argenta  49 

Tilden  formation  47 

Topography  of  Bannack  and 

Argenta  10 

Trachyte  porphyry 55 

Tuscarora  Mining  & Smelting  Co...  59 
Umpleby,  J.  B.,  reference  to.-..ll-18-39 

Vegetation  12 

Volcanic  rocks,  age  of 25 

Weed,  W.  H.,  reference  to 18-22 

Wheal  Rose  mine  38 

Willis,  B.,  reference  to  56 

Winchell,  A.  N.,  reference  to  10-18 

Wooley  mine  59 


THE  CF  THE 

OCT  i 7 1932 

UNIVERSITY  OF  ILLINOIS. 


eoqraphy£  Geo/oqy  by  fcJ.Ghenon'1925 


LEGEND 


Sedimentary  Rocks 


Aur/fe  roL/s  P/<acens 


Grc3ve/s 


¥ 

f 


IV/.  V v aonmg  i v/ii 

11.  Pioneer 

12.  Charter  Oak 

13.  Ingersoll 

14.  Lone  Star 

15.  Kent 

16.  Huron 

17.  Del  Monte 

18.  Pomeroy 

19.  Iron  Mask 

20.  Wheal  Rose 

21.  Stevenson 

22.  New  Departure 

23.  Randall 


(ONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


Bulletin  6,  Plate  I 


Igneous  Rocks 


Topography  t ieology  by  fL/Sheron'IUS 


TOPOGRAPHIC  AND  GEOLOGIC  MAP  OF  THE  BANNACK  DISTRICT 

CONTOUR  INTERVAL,  100  FEET.  SCALE.  1 INCH  EQUALS  2500  FEET. 


MON' 


MONTANA  BUREAU  OF  MINES  AND  GEOLOGY 


100 


OO 


Topography  & Geology  by  PJ  She  non  1929 


french  Creek  S V ^ 

) So 

rr  « T 1 7 1)  '•j 

— - — r — _ 

Section  C -D 


LEGEND 

Sedimentary  Rocks 


Upper  Bench  Gravots 


Pe/eozo/c  Limestone 


F/athead  Quartzite 


Spokane  Formatton 


Igneous  Rocks 


Voice  n /c  Pocks 


Andes /fe  fbrphyry 


Quartz  Kfonzonit e 


EEE3 


0) 

(f 


Section  A -B 


TOPOGRAPHIC  AND  GEOLOGIC  MAP  OF  THE  ARGENTA  DISTRICT 
SCALE,  1 INCH  EQUALS  2000  FEET. 


I.IST  OF  MINING  PROPERTIES 


1.  Tuscarora 

2.  Gov.  Tilden 

3.  Fraction 

4.  Wooley 

5.  Coolidge 

6.  Ground  Hog 

7.  Gladstone 

8.  Carbonate 

9.  Joker 
10.  Rena 


11.  Golden  Era 

12.  Dexter 

13.  Gold  Finch 

14.  Ermont 

15.  Goldsmith 

16.  Brownell 
17  Mauldin 

18.  Jack  Rabbit 

19.  Stapleton 

20.  Copper  Bell 


21.  Ferdinand 

22.  Bella 

23.  Argenta  Mining  Co. 

24.  Iron  Mountain 

25.  Midnight 

26.  Argenta 

27.  Polar  Bear 

28.  Legal  Tender 

29.  Anaconda 


CONTOUR  INTERVAL  100  FEET 


STATE  OF  MONTANA 

M.  A.  Brannon,  Chancellor,  The  University  of  Montana 

BUREAU  OF  MINES  AND  GEOLOGY 

Francis  A.  Thomson,  Director 

Montana  Bureau  of  Mines  and  Geology  Bulletin 

ISSUED  QUARTERLY— PRICE  50  CENTS 

No.  6 January,  1931 


GEOLOGY  AND  ORE  DEPOSITS  OF 
BANNACK  AND  ARGENTA, 
MONTANA 

ly 

Philip  J.  Shenon 


MONTANA  SCHOOL  OF  MINES 

BUTTE,  MONTANA 

Entered  as  second  class  matter  January,  1931,  at  the  postoffice  at  Butte,  Montana, 
under  the  Act  of  March  3,  1879. 


